Semiconductor device

ABSTRACT

[Object] A semiconductor device is configured to release heat from semiconductor chips more efficiently. [Means for Solution] A semiconductor device includes: a die pad  11  which has a die pad main surface  111  and a die pad rear surface  112 ; a semiconductor chip  41  mounted on the die pad main surface  111 ; a sealing resin portion  7  formed with a recess  75  for exposure of the die pad rear surface  11  and covering the die pad  11  and the semiconductor chip  41 ; and a heat releasing layer  6  disposed in the recess  75 . The recess  75  has a recess groove  753  outside the die pad  11  in a direction in which the die pad rear surface  112  extends, and the recess groove  753  is closer to the die pad main surface  111  than to the die pad rear surface  112 . The heat releasing layer  6  has a junction layer which is in contact with the die pad rear surface  112  and having part thereof filling the recess groove  753.

TECHNICAL FIELD

The present invention relates to semiconductor devices.

BACKGROUND ART

Conventionally, among various types of semiconductor devices, IPM(Intelligent Power Module) semiconductor devices are used in electricpower source control. These semiconductor devices, often used to controla large amount of electrical power and tending to generate heat, includea plurality of semiconductor chips, a plurality of die pads, a metallayer serving as a heatsink, a junction layer and a sealing resin. Eachof the semiconductor chips is disposed on one of the die pads. Each diepad is joined to the metal layer by the junction layer. The sealingresin covers the semiconductor chips, the die pads, the heatsink and thejunction layer. A semiconductor device so called IPM is disclosed inPatent Document 1 for example.

Such a semiconductor device is mounted on a substrate (circuitsubstrate). Under this state where the semiconductor device is mountedon a substrate, the heatsink is faced to a relatively large heatreleasing member outside of the semiconductor device. If, however, thejunction layer has a portion extending out of the sealing resin, a gapmay be made between the metal layer and the heat releasing member. Thisprevents efficient transfer of heat from the semiconductor chips to theheat releasing member.

The heat releasing layer and the sealing resin are made of differentmaterials. Due to this, the outer edge of the heat releasing layer maycome off the sealing resin. If this separation grows along the sealingresin, heat release from the semiconductor chips may be hindered and/orthe semiconductor chips may be corroded.

When bonding aluminum wires, pressure and vibration are applied to thewires. The pressure and vibration are further applied to the die padsand the wire bonding regions. If the die pads and/or the wire bondingregions vibrate or deform, however, the bonding of the wires cannot beperformed properly.

As noted above, a conventional semiconductor device may be mounted on asubstrate (circuit substrate), and in the substrate-mounted state, theheatsink is faced to a relatively large heat releasing member outside ofthe semiconductor device. Also, a plurality of semiconductor chips aremounted on the die pads via solder paste, and in addition, thick andhard wires made of aluminum, for example, are used to provide electricalconnection between each semiconductor chip with a lead so that a largeamount of electric current can pass through.

In the above-noted semiconductor device, when a plurality ofsemiconductor chips are mounted, adjacent semiconductor chips may beunduly connected to each other via solder paste. Also, there can be aproblem of so called solder erosion in which only part of the solderpaste reaches an end of the die pad. Further, there is another problemthat surface tension, for example, in the solder paste can move thesemiconductor chips out of their predetermined positions. Such a shiftof the semiconductor chips from their predetermined positions sometimesmakes it difficult to bond them with hard wires. If the semiconductorchips are spaced from each other at an increased distance in order toavoid this problem, then there is another problem that the overall sizeof the semiconductor device is increased.

REFERENCE LIST Patent Document

-   Patent Document 1: JP2009-105389A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The present invention has been proposed under the above-describedcircumstances, and it is therefore an object of the present invention toprovide a semiconductor device configured to release heat from thesemiconductor chips more efficiently.

Means for Solving the Problems

A first aspect of the present invention provides a semiconductor devicewhich includes: a die pad including a main surface and a rear surfacefacing in opposite directions; a semiconductor chip mounted on the mainsurface of the die pad; a sealing resin portion formed with a recess forexposure of the rear surface of the die pad while covering the die padand the semiconductor chip; and a heat releasing layer disposed in therecess. With this arrangement, the recess has a groove on an outer sidethan the die pad in a direction in which the rear surface extends, andthe groove is closer to the main surface than to the rear surface. Inaddition, the heat releasing layer includes a junction layer which is incontact with the rear surface of the die pad and has a part thereoffilling the groove.

According to a preferred embodiment of the present invention, the heatreleasing layer includes a metal layer which is laminated on thejunction layer to face away from the die pad.

According to a preferred embodiment of the present invention, the metallayer is made of Cu.

According to a preferred embodiment of the present invention, thejunction layer is made of a resin.

According to a preferred embodiment of the present invention, the metallayer partially protrudes in its thickness direction, from the recess.

According to a preferred embodiment of the present invention, the grooveis on an outer side with respect to the metal layer in the direction inwhich the rear surface extends.

According to a preferred embodiment of the present invention, the recessincludes a bottom surface which has a region between the metal layer andthe groove.

According to a preferred embodiment of the present invention, the grooveis slanted in such a manner that as it goes away from the die pad in thedirection in which the rear surface extends, it comes closer from therear surface side to the main surface side in the thickness direction ofthe die pad.

According to a preferred embodiment of the present invention, the recessincludes: a first side surface which is on an outer side than the diepad in the direction in which the rear surface extends, and is connectedto the bottom surface; a support surface which is connected to the firstside surface and faces in a direction in which the rear surface faces;and a second side surface which is connected to the support surface andis located between the die pad and the first side surface in thedirection in which the rear surface extends. With the above-describedarrangement, the metal layer overlaps the first side surface in athickness direction of the die pad, and has an outer edge at least partthereof being between the first side surface and the second side surfacein the direction in which the rear surface extends.

According to a preferred embodiment of the present invention, part ofthe junction layer is between the support surface and the metal layer.

A second aspect of the present invention provides a semiconductor devicewhich includes: a plurality of die pads each including a main surfaceand a rear surface facing in opposite directions; a plurality ofsemiconductor chips each mounted on the main surface of one of the diepads; a sealing resin portion formed with a recess for common exposureof the rear surfaces of at least some of the die pads while covering allof the die pads and the semiconductor chips; and a heat releasing layerdisposed in the recess. With this arrangement, the recess has a grooveon an outer side than any of the die pads on the rear surface side, on acloser side to the main surface than to the rear surface. In addition,the heat releasing layer includes a junction layer which is in contactcommonly with the rear surface of each die pad and has part thereoffilling the groove.

A third aspect of the present invention provides a semiconductor devicewhich includes: a die pad having a main surface and a rear surfacefacing in opposite directions; a semiconductor chip mounted on the mainsurface of the die pad; a sealing resin portion which is formed with arecess receding from a resin bottom surface, exposes the rear surface ofthe die pad yet covers the die pad and the semiconductor chip; and aheat releasing layer disposed in the recess. With this arrangement, therecess has: a first side surface which is positioned on an outer sidethan is the die pad in a direction in which the rear surface extends,and is connected to the resin bottom surface; a support surface which isconnected to the first side surface and faces in a direction in whichthe rear surface faces; and a second side surface which is connected tothe support surface and is between the die pad and the first sidesurface in the direction in which the rear surface extends. In addition,the heat releasing layer includes: a heat releasing layer which has anouter edge with at least part thereof located between the first sidesurface and the second side surface in the direction in which the rearsurface extends, and overlaps the first side surface in a thicknessdirection of the die pad; and a junction layer between the heatreleasing layer and the die pad.

According to a preferred embodiment of the present invention, the heatreleasing layer is made of a metal.

According to a preferred embodiment of the present invention, the metalis Cu.

According to a preferred embodiment of the present invention, thejunction layer is made of a resin.

According to a preferred embodiment of the present invention, part ofthe junction layer is between the support surface and the heat releasinglayer.

According to a preferred embodiment of the present invention, the recesshas a groove which is positioned on an outer side than is the die pad inthe direction in which the rear surface extends, and has a regionlocated on a side closer to the main surface than to the rear surface.In addition, the junction layer has its part filling the groove.

According to a preferred embodiment of the present invention, the heatreleasing layer partially protrudes in its thickness direction, from therecess.

According to a preferred embodiment of the present invention, the grooveis on an outer side with respect to the heat releasing layer in thedirection in which the rear surface extends.

According to a preferred embodiment of the present invention, the recessincludes a recess bottom surface which has a region between the heatreleasing layer and the groove.

According to a preferred embodiment of the present invention, the recessis slanted in such a manner that as it goes away from the die pad in thedirection in which the rear surface extends, it comes closer from therear surface side to the main surface side in the thickness direction ofthe die pad.

A fourth aspect of the present invention provides a semiconductor devicewhich includes: a plurality of die pads each including a main surfaceand a rear surface facing in opposite directions; a plurality ofsemiconductor chips each mounted on the main surface of one of the diepads; a sealing resin portion which is formed with a recess recedingfrom a resin bottom surface, commonly exposes the rear surfaces of atleast one or more of the die pads yet commonly covers the die pads andthe semiconductor chips; and a heat releasing layer disposed in therecess. With this arrangement, the recess, on its side facing the rearsurface, has: a first side surface which is on an outer side than is anyof the die pads and is connected to the resin bottom surface; a supportsurface which is connected to the first side surface and faces in adirection in which the rear surface faces; and a second side surfacewhich is connected to the support surface and is between the die pad andthe first side surface in a direction in which the rear surface extends,whereas the heat releasing layer includes: a heat releasing layer whichhas an outer edge with at least part thereof being between the firstside surface and the second side surface in the direction in which therear surface extends, and overlaps the first side surface in a thicknessdirection of the die pad; and a junction layer positioned between theheat releasing layer and the die pad.

A fifth aspect of the present invention provides a semiconductor devicewhich includes: a die pad having a die pad main surface and a die padrear surface facing in opposite directions; a semiconductor chip mountedon the die pad main surface; a sealing resin portion which is formedwith a recess receding from a bottom surface, exposes the die pad rearsurface yet covers the die pad and the semiconductor chip; and a heatreleasing layer which is disposed in the recess, has a heat releasinglayer main surface facing the die pad rear surface and a heat releasinglayer rear surface facing away from the heat releasing layer mainsurface, and is joined to the die pad. With this arrangement, the heatreleasing layer has: a first side surface which is positioned on anouter side than is the die pad in a direction in which the die pad rearsurface extends, and is connected to the heat releasing layer rearsurface; an intermediate surface which is connected to the first sidesurface and faces in a direction in which the heat releasing layer mainsurface faces; and a second side surface which is connected to theintermediate surface and is between the die pad and the first sidesurface in a direction in which the die pad rear surface extends.

According to a preferred embodiment of the present invention, the heatreleasing layer is made of a ceramic.

According to a preferred embodiment of the present invention, the firstside surface, the intermediate surface, and the second side surface arein contact with the sealing resin portion.

According to a preferred embodiment of the present invention, the heatreleasing layer rear surface of the heat releasing layer is flush withthe bottom surface of the sealing resin portion.

According to a preferred embodiment of the present invention, the firstside surface and the intermediate surface form a first angled region.

According to a preferred embodiment of the present invention, theintermediate surface and the second side surface form a second angledregion.

According to a preferred embodiment of the present invention, at leastone of the first angled region and the second angled region has a rightangle.

According to a preferred embodiment of the present invention, the firstside surface has a greater dimension in a thickness direction of theheat releasing layer than a dimension of the second side surface in thethickness direction of the heat releasing layer.

According to a preferred embodiment of the present invention, the heatreleasing layer and the die pad are joined to each other by a junctionlayer.

According to a preferred embodiment of the present invention, the heatreleasing layer main surface of the heat releasing layer is formed witha plurality of grooves extending in a direction perpendicular to athickness direction of the heat releasing layer.

According to a preferred embodiment of the present invention, each ofthe grooves has a rectangular section.

According to a preferred embodiment of the present invention, one ormore of the grooves are in contact with the junction layer.

According to a preferred embodiment of the present invention, one ormore of the grooves are in contact with the sealing resin portion.

A sixth aspect of the present invention provides a semiconductor devicewhich includes: a plurality of die pads each having a die pad mainsurface and a die pad rear surface facing in opposite directions; aplurality of semiconductor chips each mounted on one of the die pad mainsurfaces; a sealing resin portion which is formed with a recess recedingfrom a bottom surface, commonly exposes the die pad rear surfaces yetcommonly covers each die pad and each semiconductor chip; and a heatreleasing layer which is disposed in the recess, has a heat releasinglayer main surface facing the die pad rear surfaces and a heat releasinglayer rear surface facing away from the heat releasing layer mainsurface, and is commonly joined to each die pad. With this arrangement,the heat releasing layer has: a first side surface which is positionedon an outer side than is the die pad in a direction in which the die padrear surface extends, and is connected to the heat releasing layer rearsurface; an intermediate surface which is connected to the first sidesurface and faces in a direction in which the heat releasing layer mainsurface faces; and a second side surface which is connected to theintermediate surface and is between the die pad and the first sidesurface in the direction in which the die pad rear surface extends.

A seventh aspect of the present invention provides a wire bonding methodwhich includes a wire bonding step of bonding a wire while a pair ofpressing pieces are pressed onto two places on a bonding object at aspace from each other, onto a position in the bonding object between thepair of pressing pieces within a direction in which the pressing piecesare spaced from each other.

According to a preferred embodiment of the present invention, the wireis bonded to a place on the bonding object, across a straight line whichconnects the pair of pressing pieces, in the wire bonding step.

According to a preferred embodiment of the present invention, thebonding object includes a die pad of a metal plate and a semiconductorchip mounted on the die pad and having one or more electrodes. In thewire bonding step, the pair of pressing pieces are pressed onto placesin the die pad sandwiching the semiconductor chip while the wire isbonded to the electrodes.

According to a preferred embodiment of the present invention, thesemiconductor chip has a plurality of electrodes, and in the wirebonding step, the pair of pressing pieces are pressed onto placessandwiching the plurality of electrodes while a wire is bondedindividually to each of the electrodes.

According to a preferred embodiment of the present invention, thebonding object includes a wire bonding portion made of a metal plate,and in the wire bonding step, the pair of pressing pieces are pressedonto the wire bonding portion while a wire is bonded to the wire bondingportion.

According to a preferred embodiment of the present invention, thebonding object includes: a die pad made of a metal plate; asemiconductor chip mounted on the die pad and having one or moreelectrodes; and a wire bonding portion spaced from the die pad. In thewire bonding step, the pair of pressing pieces are pressed onto placesin the die pad sandwiching the semiconductor chip while a wire is bondedto the electrodes, and after this wire bonding step, an additional pairof pressing pieces are pressed onto the wire bonding portion and anadditional wire bonding step is performed to the wire bonding portion.

According to a preferred embodiment of the present invention, thesemiconductor chip has a plurality of electrodes, and in the wirebonding step, the pair of pressing pieces are pressed onto placessandwiching the plurality of electrodes while a wire is bondedindividually to each of the electrodes.

According to a preferred embodiment of the present invention, the wireis made of aluminum.

According to a preferred embodiment of the present invention, pressureand vibration are applied to the wire in the wire bonding step.

An eighth aspect of the present invention provides a semiconductordevice which includes: a die pad having a main surface and a rearsurface facing in opposite directions; a semiconductor chip mounted onthe main surface of the die pad and having one or more electrodes; and asealing resin portion covering the die pad and the semiconductor chip.With this arrangement, the die pad is formed with a pair of press marksspaced from each other, and a wire has an end bonded to a place on theelectrode between the pair of press marks within a direction in whichthe pair of press marks are spaced from each other.

According to a preferred embodiment of the present invention, the end ofthe wire is bonded to cross a straight line which connects the pair ofpressing pieces with each other on the electrode.

According to a preferred embodiment of the present invention, thesemiconductor device further includes a wire bonding portion spaced fromthe die pad. With this arrangement, the wire bonding portion is formedwith an additional pair of press marks spaced from each other, and thewire has another end bonded to a place on the wire bonding portionbetween the additional pair of press marks within a direction in whichthe additional pair of press marks are spaced from each other.

According to a preferred embodiment of the present invention, saidanother end of the wire is bonded across a straight line which connectsthe additional pair of press marks with each other on the wire bondingportion.

A ninth aspect of the present invention provides a semiconductor devicewhich includes: a die pad including a main surface and a rear surfacefacing in opposite directions; a semiconductor chip mounted on the mainsurface of the die pad and including one or more electrodes; leads eachelectrically connected to the semiconductor chip via a wire; and asealing resin portion covering the die pad, the semiconductor chip andpart of the leads. With this arrangement, the lead is formed with a pairof press marks on its surface to sandwich a bonding place where the wirehas its end bonded.

According to a preferred embodiment of the present invention, the leadsformed with the press marks have a wider region than the leads notformed with press marks.

According to a preferred embodiment of the present invention, the wireincludes those of different thicknesses, and the press marks are formedonly near the bonding places of the wires of a greater thickness.

According to a preferred embodiment of the present invention, thesemiconductor device includes a plurality of the semiconductor chips.With this arrangement, the thick wire is used only for electricalconnection between one or more of the semiconductor chips and the leads.

According to a preferred embodiment of the present invention, the diepad surface sandwiching the semiconductor chip is formed with a pair ofpress marks spaced from each other so as to sandwich the semiconductorchip.

According to a preferred embodiment of the present invention, thesemiconductor device includes a plurality of the semiconductor chipsincluding an output transistor and a controlling semiconductor chiptherefor. With this arrangement, the press marks spaced from each otheron the lead are formed to sandwich a place where the lead is bonded tothe output transistor.

A tenth aspect of the present invention provides a method for making asemiconductor device, where the method includes: an application step ofapplying an electrically conductive joining paste to a main surface of adie pad; a placement step of placing a semiconductor chip, which islarger than an area covered by the electrically conductive joining pasteas viewed in a direction in which the main surface faces, by causing arear surface of the semiconductor chip to contact with the electricallyconductive joining paste in a manner such that the area covered by theelectrically conductive joining paste is contained by the rear surfaceas viewed in the direction in which the main surface faces; and ajoining step of softening and then hardening the electrically conductivejoining paste thereby forming an electrically conductive joiningmaterial.

According to a preferred embodiment of the present invention, theelectrically conductive joining paste is provided by a solder paste.

According to a preferred embodiment of the present invention, the mainsurface is covered by a mask which has openings, and the openings arefilled with the electrically conductive joining paste in the applicationstep.

According to a preferred embodiment of the present invention, the rearsurface of the semiconductor chip has a higher wettability to theelectrically conductive joining paste than the main surface of the diepad.

According to a preferred embodiment of the present invention, the rearsurface of the semiconductor chip is made of Ag, Au, Ni or an alloycontaining one of these metals whereas the main surface of the die padis made of Cu, an FeNi alloy or Fe.

An eleventh aspect of the present invention provides a semiconductordevice which includes: a die pad having a main surface; a semiconductorchip having a rear surface; and an electrically conductive joiningmaterial between the main surface of the die pad and the rear surface ofthe semiconductor chip, providing a junction between the die pad and thesemiconductor chip. With this arrangement, the rear surface of thesemiconductor chip and the electrically conductive joining materialshare a larger junction area between the two than do the main surface ofthe die pad and the electrically conductive joining material.

According to a preferred embodiment of the present invention, theelectrically conductive joining material is provided by a solder.

According to a preferred embodiment of the present invention, the rearsurface of the semiconductor chip has a higher wettability to theelectrically conductive joining paste than the main surface of the diepad.

According to a preferred embodiment of the present invention, the rearsurface of the semiconductor chip is made of Ag, Au, Ni or an alloycontaining one of these metals, whereas the main surface of the die padis made of Cu, an FeNi alloy or Fe.

A twelfth aspect of the present invention provides a semiconductordevice which includes: die pads each having a main surface and a rearsurface facing in opposite directions; a plurality of semiconductorchips each mounted on the main surface of one of the die pads; and anelectrically conductive joining material between the main surface ofeach die pad and a rear surface of each semiconductor chip, providing ajunction between the die pad and the semiconductor chip. With thisarrangement, the rear surface of each semiconductor chip shares with itscorresponding electrically conductive joining material a larger junctionarea between the two than does the main surface of said die pad sharewith said electrically conductive joining material formed for saidsemiconductor chip.

According to a preferred embodiment of the present invention, thesemiconductor chip includes a plurality of output transistors and acontrolling semiconductor chip therefor, the above-describedrelationship between two junction areas being true in the plurality ofoutput transistors.

According to a preferred embodiment of the present invention, thesemiconductor device further includes: a plurality of leads each for anoutput from one of the output transistors; and a plurality of wires eachconnecting one of the output transistors with a corresponding one of theleads; the wire being made of aluminum.

Other characteristics and advantages of the present invention willbecome clearer from the following detailed description to be made withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a packaging structure of asemiconductor device according to Embodiment 1A of the presentinvention.

FIG. 2 is a plan view (partially unillustrated) of the semiconductordevice according to Embodiment 1A of the present invention, before leadsare bent.

FIG. 3 is a bottom view of the semiconductor device according toEmbodiment 1A of the present invention, before leads are bent.

FIG. 4 is a sectional view taken in lines IV-IV in FIG. 2.

FIG. 5 is an enlarged sectional view of a primary portion taken fromFIG. 4.

FIG. 6 is a plan view showing a manufacturing step of the semiconductordevice according to Embodiment 1A of the present invention.

FIG. 7 is a sectional view showing a step which follows the one in FIG.6.

FIG. 8 is a sectional view showing a step which follows the one in FIG.7.

FIG. 9 is a sectional view showing a step which follows the one in FIG.8.

FIG. 10 is a bottom view of a semiconductor device according toEmbodiment 2A of the present invention, before leads are bent

FIG. 11 is an enlarged sectional view taken in lines XI-XI in FIG. 10.

FIG. 12 is a sectional view showing a packaging structure of asemiconductor device according to Embodiment 1B of the presentinvention.

FIG. 13 is a plan view (partially unillustrated) of a semiconductordevice according to Embodiment 1B of the present invention, before leadsare bent.

FIG. 14 is a bottom view of a semiconductor device according toEmbodiment 1B of the present invention, before the leads are bent.

FIG. 15 is a sectional view taken in lines XV-XV in FIG. 13.

FIG. 16 is an enlarged sectional view of a primary portion taken fromFIG. 15.

FIG. 17 is a plan view showing a manufacturing step of the semiconductordevice according to Embodiment 1B of the present invention.

FIG. 18 is a sectional view showing a step which follows the one in FIG.17.

FIG. 19 is a sectional view showing a step which follows the one in FIG.18.

FIG. 20 is a sectional view showing a step which follows the one in FIG.19.

FIG. 21 is a bottom view of a semiconductor device according toEmbodiment 2B of the present invention, before leads are bent.

FIG. 22 is an enlarged sectional view taken in lines XXII-XXII in FIG.21.

FIG. 23 is a sectional view showing a packaging structure of asemiconductor device according to Embodiment 10 of the presentinvention.

FIG. 24 is a plan view (partially unillustrated) of a semiconductordevice according to Embodiment 10 of the present invention, before leadsare bent.

FIG. 25 is a bottom view of a semiconductor device according toEmbodiment 1C of the present invention, before the leads are bent.

FIG. 26 is a sectional view taken in lines XXVI-XXVI in FIG. 24.

FIG. 27 is an enlarged sectional view of a primary portion taken fromFIG. 26.

FIG. 28 is a plan view showing a manufacturing step of the semiconductordevice according to Embodiment 10 of the present invention.

FIG. 29 is a sectional view showing a step which follows the one in FIG.28.

FIG. 30 is a sectional view showing a semiconductor device according toEmbodiment 2C of the present invention.

FIG. 31 is a plan view showing a heat releasing layer of thesemiconductor device in FIG. 30.

FIG. 32 is a sectional view showing a packaging structure of asemiconductor device according to Embodiment 1D of the presentinvention.

FIG. 33 is a plan view (partially unillustrated) of the semiconductordevice according to Embodiment 1D of the present invention, before leadsare bent.

FIG. 34 is a plan view of a primary portion in the semiconductor deviceaccording to Embodiment 1D of the present invention.

FIG. 35 is a bottom view of a semiconductor device according toEmbodiment 1D of the present invention, before the leads are bent.

FIG. 36 is a sectional view taken in lines XXXVI-XXXVI in FIG. 33.

FIG. 37 is a plan view showing a manufacturing step of the semiconductordevice according to Embodiment 1D of the present invention.

FIG. 38 is a side view of an example of bonding apparatus used in a wirebonding method according to the present invention.

FIG. 39 is a perspective view of a primary portion, showing amanufacturing step of the semiconductor device according to Embodiment1D of the present invention.

FIG. 40 is a perspective view of a primary portion, showing a step whichfollows the one in FIG. 39.

FIG. 41 is a perspective view of a primary portion, showing a step whichfollows the one in FIG. 40.

FIG. 42 is a perspective view of a primary portion, showing a step whichfollows the one in FIG. 41.

FIG. 43 is a perspective view of a primary portion, showing a step whichfollows the one in FIG. 42.

FIG. 44 is a plan view of a primary portion, showing a step whichfollows the one in FIG. 42.

FIG. 45 is a plan view showing a step which follows the one in FIG. 42.

FIG. 46 is a sectional view showing a step which follows the one in FIG.45.

FIG. 47 is a sectional view showing a step which follows the one in FIG.46.

FIG. 48 is a sectional view showing a step which follows the one in FIG.47.

FIG. 49 is a sectional view showing a packaging structure of asemiconductor device according to Embodiment 1E of the presentinvention.

FIG. 50 is a plan view (partially unillustrated) of the semiconductordevice according to Embodiment 1E of the present invention, before leadsare bent.

FIG. 51 is a bottom view of a semiconductor device according toEmbodiment 1E of the present invention, before the leads are bent.

FIG. 52 is a sectional view taken in lines LII-LII in FIG. 50.

FIG. 53 is an enlarged sectional view of a primary portion taken fromFIG. 52.

FIG. 54 is a plan view showing a manufacturing step of the semiconductordevice according to Embodiment 1E of the present invention.

FIG. 55 is an enlarged sectional view of a primary portion, showing astep which follows the one in FIG. 54.

FIG. 56 is an enlarged sectional view of a primary portion, showing astep which follows the one in FIG. 55.

FIG. 57 is an enlarged sectional view of a primary portion, showing astep which follows the one in FIG. 56.

FIG. 58 is an enlarged sectional view of a primary portion, showing astep which follows the one in FIG. 57.

FIG. 59 is an enlarged sectional view of a primary portion, showing astep which follows the one in FIG. 58.

FIG. 60 is a plan view showing a step which follows the one in FIG. 59.

FIG. 61 is a plan view showing a step which follows the one in FIG. 60.

FIG. 62 is a sectional view showing a step which follows the one in FIG.61.

FIG. 63 is a sectional view showing a step which follows the one in FIG.62.

FIG. 64 is a sectional view showing a step which follows the one in FIG.63.

MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be described belowwith reference to the drawings.

FIG. 1 is a sectional view showing a packaging structure when use ismade of a semiconductor device according to Embodiment 1A of the presentinvention.

A semiconductor device packaging structure 801 shown in FIG. 1 includesa semiconductor device 101A, a substrate 807 and a heat releasing member808.

The substrate 807 is a member on which a plurality of electriccomponents are mounted. The substrate 807 is made of an insulatingmaterial. The substrate 807 is formed with an unillustrated wiringpattern. The substrate 807 is formed with a plurality of holes 809. Theheat releasing member 808 is made of a material which has a relativelyhigh heat conductivity like a metal such as aluminum. The heat releasingmember 808 is fixed to the substrate 807 by an unillustrated supportingmember. The semiconductor device 101A is mounted on the substrate 807.In the present embodiment, the semiconductor device 101A is a so calledIPM (Intelligent Power Module). The semiconductor device 101A is usedfor such an application as electric power source control in an airconditioner, a motor controller, etc.

FIG. 2 is a plan view (partially unillustrated) of the semiconductordevice according to Embodiment 1A of the present invention, in a statebefore leads are bent. FIG. 3 is a bottom view of the semiconductordevice according to Embodiment 1A of the present invention, in a statebefore the leads are bent. FIG. 4 is a sectional view taken in linesIV-IV in FIG. 2. FIG. 5 is an enlarged sectional view of a primaryportion taken from FIG. 4. FIG. 1 represents a section taken in linesI-I in FIG. 2. In FIG. 4, each component is illustrated schematicallyfor easier comprehension.

The semiconductor device 101A shown in these drawings includes aplurality of first electrode portions 1, second electrode portions 2 andthird electrode portions 3; a plurality of the semiconductor chips 41,42; passive component chips 43; a heat releasing layer 6; a sealingresin portion 7 and wires 8. FIG. 2 shows the heat releasing layer 6 inbroken lines and the sealing resin portion 7 in imaginary lines.

The sealing resin portion 7 covers the first electrode portions 1, thesecond electrode portions 2, the third electrode portions 3, thesemiconductor chips 41, 42, and the passive component chips 43. Thesealing resin portion 7 is made of a black epoxy resin for example. Asshown in FIGS. 3 and 4, the sealing resin portion 7 has a resin mainsurface 71, a resin bottom surface 72 and a resin side surface 73.

The resin main surface 71 is a flat surface which faces in a directionz1 and extends along an xy plane. The resin bottom surface 72 is a flatsurface which faces in a direction z2 that is opposite to the directionz1 and extends along an xy plane. The resin side surface 73 surroundsthe semiconductor chips 41, 42 and the passive component chips 43 inxy-plane view. The resin side surface 73 is connected to the resin mainsurface 71 and the resin bottom surface 72.

As clearly shown in FIG. 4, the sealing resin portion 7 is formed with arecess 75. The recess 75 recedes from the resin bottom surface 72. Therecess 75 has a recess bottom surface 751, a recess side surface 752,and a recess groove 753. The recess bottom surface 751 extends along anxy plane. The recess side surface 752 is connected to the resin bottomsurface 72. The recess side surface 752 extends substantially in adirection z.

In the preset embodiment, the recess groove 753 is between the recessbottom surface 751 and the recess side surface 752, and is configured ina rectangular-annular pattern along the outer edge of the recess 75 asviewed in the z direction. As shown in FIG. 5, the recess groove 753recedes from the recess bottom surface 751 in a z1 direction. In thepresent embodiment, the recess groove 753 is disposed on an outside of ametal layer 65 as viewed in the z direction. In addition, the recessgroove 753 is slanted in such a manner that as it goes away from therecess bottom surface 751 in the x direction, it also goes away from thesurface 751 in the z1 direction. The recess groove 753 has a maximumdepth of approximately 50 μm for example.

As shown in FIG. 2, the semiconductor chips 41, 42 and the passivecomponent chips 43 are rectangular in plan view. The semiconductor chip41 is a power chip such as an IGBT, MOS, and diode. The semiconductorchip 42 is an LSI chip such as a control IC. The passive component chips43 are, for example, resisters, capacitors or other passive components.

The first electrode portions 1, the second electrode portions 2 and thethird electrode portions 3 in FIG. 2 through 4 are all made of anelectrically conductive material. An example of such an electricallyconductive material is copper. The electrode portion shown in a bottomright region in FIG. 2 is grounded.

Each of the plurality (four, in the present embodiment) of the firstelectrode portions 1 includes a die pad 11 (see FIG. 1, FIG. 2, FIG. 4),a connecting region 12 (see FIG. 1, FIG. 2), a wire bonding region 13(see FIG. 1, FIG. 2) and a lead 14 (see FIG. 1 through FIG. 3). Thefirst electrode portions 1 are spaced from each other in the directionx.

Each die pad 11 is a flat plate extending along and parallel to an xyplane. The semiconductor chip 41 is disposed on the die pad 11. As shownin FIG. 4, a junction layer 991 is between the die pad 11 and thesemiconductor chip 41. The junction layer 991 is made of an electricallyconductive material. The electrically conductive material is provided bysolder or silver paste, for example. Solder has a relatively highthermal conductivity. Use of solder as the junction layer 991 enablesefficient heat conduction from the semiconductor chip 41 to the die pad11. Each of the die pads 11 is exposed from the recess bottom surface751.

Each die pad 11 has a die pad main surface 111 and a die pad rearsurface 112. The die pad main surface 111 faces in the direction z1whereas the die pad rear surface 112 faces in the direction z2. In otherwords, the die pad main surface 111 and the die pad rear surface 112 arearranged to face away from each other, i.e., face in the mutuallyopposite directions. The semiconductor chip 41 is disposed on the diepad main surface 111. The junction layer 991 is between the die pad mainsurface 111 and the semiconductor chip 41. The die pad rear surface 112is located at the same position as the recess bottom surface 751 in athickness direction (the direction z) of the die pad 11. However, thedie pad rear surface 112 may be closer to an opening of the recess 75than is the recess bottom surface 751.

As shown in FIG. 2, each connecting region 12 is disposed between thedie pad 11 and the wire bonding region 13, and connected to the die pad11 and to the wire bonding region 13. As shown in FIG. 1, the connectingregion 12 extends along a plane which is inclined with respect to an xyplane. The connecting region 12 is inclined with respect to an xy planein such a manner that it goes farther in the direction z1 as it isfurther away from the die pad 11.

Each wire bonding region 13 shown in FIG. 1 and FIG. 2 extends along anxy plane. In the direction z, each wire bonding region 13 is on a sidemore toward the direction z1 than is the die pad 11. A wire 8 is bondedto one of the wire bonding regions 13 and to one of the semiconductorchips 41. Thus, electrical conductivity is established between said oneof the wire bonding regions 13 and said one of the semiconductor chips41. The leads 14 are connected to the wire bonding regions 13. Each lead14 extends along the direction y. The lead 14 has a portion extendingout of the resin side surface 73 of the sealing resin portion 7. In thepresent embodiment, the leads 14 are for insertion mounting. As shown inFIG. 1, when mounting the semiconductor device 101A on the substrate807, the leads 14 are bent and inserted through the holes 809. Forfixing the leads 14 in the substrate 807, the holes 809 are filled withsolder layers 810.

As shown in FIG. 2, each of the plurality (three, in the presentembodiment) of the second electrode portions 2 includes a wire bondingregion 23 and a lead 24. The second electrode portions 2 are spaced fromeach other in the direction x.

Each wire bonding region 23 extends along an xy plane. In the directionz, each wire bonding region 23 is on a side more toward the direction z1than is the die pad 11. A wire 8 is bonded to one of the wire bondingregions 23 and to one of the semiconductor chips 41. Thus, electricalconductivity is established between said one of the wire bonding regions23 and said one of the semiconductor chips 41. The leads 24 areconnected to the wire bonding regions 23. Each lead 24 extends along thedirection y. The lead 24 has a portion extending out of the resin sidesurface 73 of the sealing resin portion 7. In the present embodiment,the leads 24 are for insertion mounting. Though not illustrated, whenmounting the semiconductor device 101A on the substrate 807, the leads24 are bent and inserted through the holes 809 like the leads 14.

The third electrode portions 3 shown in FIG. 1, FIG. 2 includes aplurality of control die pads 31 and a plurality of leads 32. Thecontrol die pads 31 and the leads 32 are respectively disposed at thesame positions in the direction z. On each control die pad 31, thesemiconductor chip 42 or the passive component chips 43 is disposed. Ajunction layer (not illustrated) is formed between the control die pad31 and the semiconductor chip 42, and between the control die pads 31and the passive component chips 43. The control die pads 31 need nothave its rear surface faced to the heat releasing layer 6 or exposed.

Each lead 32 has a portion extending out of the resin side surface 73 ofthe sealing resin portion 7. In the present, embodiment, the leads 32are for insertion mounting. As shown in FIG. 1, when mounting thesemiconductor device 101A on the substrate 807, the leads 32 are bentand inserted through the holes 809. As has been described in relationwith the leads 14, the holes 809 are filled with solder layers 810 forfixing the leads 32 in the substrate 809. A wire 8 is bonded to one ofthe leads 32 and to one of the semiconductor chips 42. Thus, electricalconductivity is established between said one of the leads 32 and saidone of the semiconductor chips 42. Also, a wire 8 is bonded to one ofthe semiconductor chip 42 and to one of the passive component chips 43.

As shown in FIG. 4, the heat releasing layer 6 is in the recess 75 inthe sealing resin portion 7. The heat releasing layer 6 is surrounded bythe recess side surface 752. In the present embodiment, the heatreleasing layer 6 is a flat plate extending along and parallel to an xyplane. In the present embodiment, the heat releasing layer 6 isconstituted by the metal layer 65 and the junction layer 66. The metallayer 65 is on a z2 side of the junction layer 66, and is made of Cu,aluminum or ceramics, for example, having a thickness of approximately105 μm. The junction layer 66 is on a z1 side of the metal layer 65 andjoins the metal layer 65 to the die pad rear surfaces 112 of therespective die pads 11. The junction layer 66 is made of an insulatingresin for example, and has a thickness of approximately 250 μm forexample. The resin becomes soft when it receives pressure and vibrationin a manufacturing step of the semiconductor device 101A. The junctionlayer 66 is in direct contact with all of the die pads 11 on which thesemiconductor chips 41 are mounted. The metal layer 65 may have a regionprotruding slightly beyond the resin bottom surface 72. As shown in FIG.5, a part of the junction layer 66 fills the recess groove 753. The heatreleasing layer 66 is in contact with the recess side surface 752.

The heat releasing layer 6 is for quickly releasing heat which wasgenerated in the semiconductor chip 41 to outside of the semiconductordevice 101A. In order to quickly release the heat generated by thesemiconductor chip 41 to outside of the semiconductor device 101A, theheat releasing layer 6 should be made of a material of a large thermalconductivity. While a larger thermal conductivity is preferred, therecan be a potential problem that the metal layer 65 will come off if theheat releasing layer's thermal expansion coefficient differs greatlyfrom that of the sealing resin portion 7. Preferably, therefore, theheat releasing layer 6 is of a material which has a larger thermalconductivity than that of a material which constitutes the sealing resinportion 7, and a similar thermal expansion coefficient to that of thematerial which constitutes the sealing resin portion 7. The heatreleasing layer 6 is faced directly to all of the die pads 11. As shownin FIG. 3, the heat releasing layer 6 covers all of the die pads 11entirely in xy plane view (i.e., as viewed in the thickness direction ofthe heat releasing layer 6).

As shown in FIG. 3 and FIG. 4, the heat releasing layer 6 has a heatreleasing layer main surface 61 and a heat releasing layer rear surface62. The heat releasing layer main surface 61 faces in the direction z1.The heat releasing layer main surface 61 covers the die pad rearsurfaces 112 and the recess bottom surfaces 751 of all of the die pads11 in xy-plane view. The heat releasing layer main surface 61 is indirect contact with the die pad rear surface 112 and the recess bottomsurface 751. The heat releasing layer rear surface 62 faces in thedirection z2 which is a direction opposite to the direction in which theheat releasing layer main surface 61 faces. The heat releasing layerrear surface 62 is not covered by the sealing resin portion 7 and isexposed from the sealing resin portion 7.

Next, a method of making the semiconductor device 101A will bedescribed. Drawings for describing the method will use the samereference symbols as those used thus far in identifying those describedthus far.

First, as shown in FIG. 6, a lead frame 300 which includes a pluralityof die pads 11, 31; and a plurality of semiconductor chips 41, 42 andpassive component chips 43 is prepared. Next, as shown in the drawing,each of the semiconductor chips 41 is disposed on one of the die pads 11via the junction layer (not illustrated). Likewise, each of thesemiconductor chip 42 and the passive component chips 43 is disposed onone of the control die pads 31 via the junction layer (not illustrated).Next, as shown in the drawing, a wire 8 is bonded to each of thesemiconductor chips 41, 42 and other components.

Next, as shown in FIG. 7 and FIG. 8, a sealing resin portion 7 isformed. As shown in FIG. 7, the formation of the sealing resin portion 7is performed by means of a molding method using a metal mold 881. Asshown in the drawing, the die pads 11 and other components are pressedby the metal mold 881. Next, a resin material is injected into the metalmold 881, and then the resin material is allowed to set. Once the resinmaterial is set, the metal mold 881 is taken away from the die pads 11and other components as shown in FIG. 8. Thus, the sealing resin portion7 is formed. In the steps of forming the sealing resin portion 7, arecess 75 is formed in the sealing resin portion 7 for exposure of thedie pads 11.

Next, as shown in FIG. 9, a heat releasing layer 6 is fitted into therecess 75 of the sealing resin portion 7. Then, pressure and vibrationare applied to the heat releasing layer 6. The heat releasing layer 6may be heated, in addition. The pressure, vibration and heat soften thejunction layer 66 of the heat releasing layer 6. The softened junctionlayer 66 moves within the recess 75, with part thereof filling therecess groove 753. Also, the junction layer 66 becomes in contact withthe recess side surface 752.

Next, the lead frame 300 shown in FIG. 6 is appropriately cut tocomplete the manufacture of the semiconductor devices 101A which isillustrated in FIG. 2, etc.

Next, functions of the present embodiment will be described.

According to the semiconductor device 101A, part of the junction layer66 fills the recess groove 753. To the extent the groove is filled, itis possible to prevent the junction layer 66 from flowing over therecess 75 in the manufacturing step of the semiconductor device 101A.Therefore, it is possible to prevent the junction layer 66 fromoverflowing to outside of the metal layer 65, and hence to prevent a gapfrom being made between the heat releasing layer 6 and the heatreleasing member 808. Thus, it is possible to efficiently release heatwhich comes from the semiconductor chips 41, 42.

By disposing the recess groove 753 on an outer side of the metal layer65, it becomes possible to prevent an unintended gap from being madebetween the metal layer 65 and the recess groove 753. Eliminating thegap facilitates heat release while making it less likely that the metallayer 65 will come off.

By shaping the recess groove 753 into a taper, it becomes possible toreduce the area of the recess groove 753 which overlaps the metal layer65 as viewed in the z direction even if there is some misalignment inthe x direction or in the y direction when positioning the metal layer65. This is preferable in eliminating the gap described above.

FIG. 10 and FIG. 11 show a semiconductor device according to Embodiment2A of the present invention. In these figures, elements identical withor similar to those in the previous embodiment described above areindicated by the same reference symbols as in the previous embodiment. Asemiconductor device 102A according to the present embodiment differsfrom the semiconductor device 101A in terms of the recess 75.

In the present embodiment, the recess 75 has a plurality of recessgrooves 753 and further, a plurality of the recess first side surfaces754, the recess second side surfaces 755, and recess support surfaces756. As shown in FIG. 10, the recess grooves 753, and the recess firstside surfaces 754, the recess second side surfaces 755 and the recesssupport surfaces 756 are disposed alternatingly along an outer edge ofthe recess 75. The recess first side surfaces 754, the recess secondside surfaces 755 and the recess support surfaces 756 are disposed atfour corner regions of the recess 75.

As shown in FIG. 11, the recess first side surface 754 is connected tothe resin bottom surface 72 and is substantially in a direction z. Therecess first side surface 754 is on an outside of the die pad 11 asviewed in the z direction. The recess second side surface 755 isconnected to the recess bottom surface 751 and is substantially in thedirection z. The recess second side surface 755 is between the die pad11 and the recess first side surface 754 as viewed in the z direction.The recess support surface 756 connects the recess first side surface754 and the recess second side surface 755 with each other and facessubstantially a direction z2.

In the present embodiment, a region surrounded by the recess second sidesurfaces 755 is filled with the junction layer 66. Also, part of thejunction layer 66 is between the metal layer 65 and the recess supportsurfaces 756.

The semiconductor device 102A provides the advantages provided by thesemiconductor device 101A and in addition, an advantage that the metallayer 65 is supported at least indirectly by the recess support surfaces756. Therefore, it is possible to prevent such a problem that the metallayer 65 will become unduly slanted with respect to the resin bottomsurface 72 or become receded. Thus, it is possible to reduce cases wherea gap will be made between the metal layer 65 and the heat releasingmember 808 which is tightly fitted thereto, and to increase heat releasefrom the semiconductor chips 41, 42.

By providing the junction layer 66 between the metal layer 65 and therecess support surfaces 756, it becomes possible to reliably fix themetal layer 65 to the sealing resin portion 7. If the junction layer 66has any end regions not covered by the metal layer 65, such a region canbe a place where the metal layer 65 will start to come off. Such alikelihood is low according to the present embodiment.

The present invention is not limited to the Embodiments described above.The present invention may be varied in many ways in any specificdetails. For example, as far as the metal layer is exposed from thesealing resin rear surface, the semiconductor device may not necessarilybe of an insertion mounting type but may have terminals for surfacemounting. Also, the invention is applicable not only to IPM devicesmentioned earlier but also to a semiconductor device which includes onlyone semiconductor chip and an island but has a metal layer exposed froma rear surface of a sealing resin.

FIG. 12 is a sectional view showing a packaging structure when use ismade of a semiconductor device according to Embodiment 1B of the presentinvention.

A semiconductor device packaging structure 801 shown in FIG. 12 includesa semiconductor device 101B, a substrate 807 and a heat releasing member808.

The substrate 807 is capable of having a plurality of electriccomponents mounted thereon. The substrate 807 is made of an insulatingmaterial. The substrate 807 is formed with an unillustrated wiringpattern. The substrate 807 is formed with a plurality of holes 809. Theheat releasing member 808 is made of a material which has a relativelyhigh heat conductivity like a metal such as aluminum. The heat releasingmember 808 is fixed to the substrate 807 by an unillustrated supportingmember. The semiconductor device 101B is mounted on the substrate 807.In the present embodiment, the semiconductor device 101B is a so calledIPM (Intelligent Power Module) product. The semiconductor device 101B isused for such an application as electric power source control in an airconditioner, a motor controller, etc.

FIG. 13 is a plan view (partially unillustrated) of the semiconductordevice according to Embodiment 1B of the present invention, before leadsare bent. FIG. 14 is a bottom view of the semiconductor device accordingto Embodiment 1B of the present invention, before the leads are bent.FIG. 15 is a sectional view taken in lines XV-XV in FIG. 13. FIG. 16 isan enlarged sectional view of a primary portion taken from FIG. 15. FIG.12 represents a section taken in lines XII-XII in FIG. 13. In FIG. 15,each component is illustrated schematically for easier comprehension.

The semiconductor device 101B shown in these drawings includes aplurality of first electrode portions 1, second electrode portions 2 andthird electrode portions 3; a plurality of semiconductor chips 41, 42;passive component chips 43; a heat releasing layer 6; a sealing resinportion 7 and wires 8. FIG. 13 shows the heat releasing layer 6 inbroken lines and the sealing resin portion 7 in imaginary lines.

The sealing resin portion 7 covers the plurality of the first electrodeportions 1, the second electrode portions 2, and the third electrodeportions 3; the semiconductor chips 41, 42; and the passive componentchips 43. The sealing resin portion 7 is made of a black epoxy resin forexample. As shown in FIG. 14 and FIG. 15, the sealing resin portion 7has a resin main surface 71, a resin bottom surface 72 and a resin sidesurface 73.

The resin main surface 71 is a flat surface which faces in a directionz1 and extends along an xy plane. The resin bottom surface 72 is a flatsurface which faces in a direction z2 that is opposite to the directionz1 and extends along an xy plane. The resin side surface 73 surroundsthe semiconductor chips 41, 42 and the passive component chips 43 inxy-plane view. The resin side surface 73 is connected to the resin mainsurface 71 and the resin bottom surface 72.

As clearly shown in FIG. 15, the sealing resin portion 7 is formed witha recess 75. The recess 75 recedes from the resin bottom surface 72. Therecess 75 has a recess bottom surface 751, a recess first side surface754, a recess second side surface 755 and a recess support surface 756.The recess bottom surface 751 extends along an xy plane. The recess sidesurface 752 is connected to the resin bottom surface 72.

As shown in FIG. 16, the recess first side surface 754 is connected tothe resin bottom surface 72 and is substantially in a direction z. Therecess first side surface 754 is on an outside of the die pad 11 asviewed in the z direction. The recess second side surface 755 isconnected to the recess bottom surface 751 and is substantially in thedirection z. The recess second side surface 755 is between the die pad11 and the recess first side surfaces 754 as viewed in the z direction.The recess support surface 756 connects the recess first side surfaces754 and the recess second side surfaces 755 with each other and facessubstantially a direction z2.

As shown in FIG. 13, the semiconductor chips 41, 42 and the passivecomponent chips 43 are rectangular in plan view. The semiconductor chip41 is a power chip such as an IGBT, MOS, and diode. The semiconductorchip 42 is an LSI chip such as a control IC. The passive component chips43 are, for example, resisters, capacitors or other passive components.

The first electrode portions 1, the second electrode portions 2 and thethird electrode portions 3 in FIG. 13 are all made of an electricallyconductive material. An example of such an electrically conductivematerial is copper. The electrode portion shown in a bottom right regionin FIG. 13 is grounded.

Each of the plurality (four, in the present embodiment) of the firstelectrode portions 1 includes a die pad 11 (see FIG. 12, FIG. 13 andFIG. 15), a connecting region 12 (see FIG. 12 and FIG. 13), a wirebonding region 13 (see FIG. 12 and FIG. 13) and a lead 14 (see FIG. 12through FIG. 14). The first electrode portions 1 are spaced from eachother in the direction x.

Each die pad 11 is a flat plate extending along and parallel to an xyplane. The semiconductor chip 41 is disposed on the die pad 11. As shownin FIG. 15, a junction layer 991 is between the die pad 11 and thesemiconductor chip 41. The junction layer 991 is made of an electricallyconductive material. The electrically conductive material is provided bysolder or silver paste, for example. Solder has a relatively largethermal conductivity. Use of solder as the junction layer 991 enablesefficient heat conduction from the semiconductor chip 41 to the die pad11. Each of the die pads 11 is exposed from the recess bottom surface751.

Each die pad 11 has a die pad main surface 111 and a die pad rearsurface 112. The die pad main surface 111 faces in the direction z1whereas the die pad rear surface 112 faces in the direction z2. In otherwords, the die pad main surface 111 and the die pad rear surface 112 arearranged to face in the mutually opposite directions. The semiconductorchip 41 is disposed on the die pad main surface ill. A junction layer991 is between the die pad main surface 111 and the semiconductor chip41. The die pad rear surface 112 is located at the same position as therecess bottom surface 751 in a thickness direction (the direction z) ofthe die pad 11. However, the die pad rear surface 112 may be closer toan opening of the recess 75 than is the recess bottom surface 751.

As shown in FIG. 13, each connecting region 12 is disposed between thedie pad 11 and the wire bonding region 13, and connected to the die pad11 and to the wire bonding region 13. As shown in FIG. 12, theconnecting region 12 extends along a plane which is inclined withrespect to an xy plane. The connecting region 12 is inclined withrespect to an xy plane in such a manner that it goes farther in thedirection z1 as it is further away from the die pad 11.

Each wire bonding region 13 shown in FIG. 12 and FIG. 13 extends alongan xy plane. In the direction z, each wire bonding region 13 is on aside more toward the direction z1 than is the die pad 11. A wire 8 isbonded to one of the wire bonding regions 13 and to one of thesemiconductor chips 41. Thus, electrical conductivity is establishedbetween said one of the wire bonding regions 13 and said one of thesemiconductor chips 41. The leads 14 are connected to the wire bondingregions 13. Each lead 14 extends along the direction y. The lead 14 hasa portion extending out of the resin side surface 73 of the sealingresin portion 7. In the present embodiment, the leads 14 are forinsertion mounting. As shown in FIG. 12, when mounting the semiconductordevice 101B on the substrate 807, the leads 14 are bent and insertedthrough the holes 809. For fixing the leads 14 in the substrate 807, theholes 809 are filled with solder layers 810.

As shown in FIG. 13, each of the plurality (three, in the presentembodiment) of the second electrode portions 2 includes a wire bondingregion 23 and a lead 24. The second electrode portions 2 are spaced fromeach other in the direction x.

Each wire bonding region 23 extends along an xy plane. In the directionz, each wire bonding region 23 is on a side more toward the direction z1than is the die pad 11. A wire 8 is bonded to one of the wire bondingregions 23 and to one of the semiconductor chips 41. Thus, electricalconductivity is established between said one of the wire bonding regions23 and said one of the semiconductor chips 41. The leads 24 areconnected to the wire bonding regions 23. Each lead 24 extends along thedirection y. The lead 24 has a portion extending out of the resin sidesurface 73 of the sealing resin portion 7. In the present embodiment,the leads 24 are for insertion mounting. Though not illustrated, whenmounting the semiconductor device 101B on the substrate 807, the leads24 are bent and inserted through the holes 809 like the leads 14.

The third electrode portions 3 shown in FIG. 12, FIG. 13 includes aplurality of control die pads 31 and a plurality of leads 32. Thecontrol die pads 31 and the leads 32 are respectively disposed at thesame positions in the direction z. On each control die pad 31, thesemiconductor chip 42 or the passive component chips 43 is disposed. Ajunction layer (not illustrated) is formed between the control die pad31 and the semiconductor chip 42, and between the control die pads 31and the passive component chips 43. The control die pads 31 need nothave its rear surface faced to the heat releasing layer 6 or exposed.

Each lead 32 has a portion extending out of the resin side surface 73 ofthe sealing resin portion 7. In the present embodiment, the leads 32 arefor insertion mounting. As shown in FIG. 12, when mounting thesemiconductor device 101B on the substrate 807, the leads 32 are bentand inserted through the holes 809. As has been described in relationwith the leads 14, the holes 809 are filled with solder layers 810 forfixing the leads 32 in the substrate 809. A wire 8 is bonded to one ofthe leads 32 and to one of the semiconductor chips 42. Thus, electricalconductivity is established between said one of the leads 32 and saidone of the semiconductor chips 42. Also, a wire 8 is bonded to one ofthe semiconductor chip 42 and to one of the passive component chips 43.

As shown in FIG. 15, the heat releasing layer 6 is in the recess 75 inthe sealing resin portion 7. The heat releasing layer 6 is surrounded bythe recess first side surface 754 and the recess second side surface755. In the present embodiment, the heat releasing layer 6 is a flatplate extending along and parallel to an xy plane. In the presentembodiment, the heat releasing layer 6 is constituted by the metal layer65 and the junction layer 66. The metal layer 65 is on a side toward thez2 direction, and is made of Cu, aluminum or ceramics, for example,having a thickness of approximately 105 μm. The metal layer 65represents an example of the heat releasing layer so termed in thepresent invention. The junction layer 66 is on a side toward the z1direction with respect to the metal layer 65 and joins the metal layer65 to the die pad rear surfaces 112 of the die pads 11. The junctionlayer 66 is made of an insulating resin for example, and has a thicknessof approximately 250 μm for example. The resin becomes soft when itreceives pressure and vibration in a manufacturing step of thesemiconductor device 101B. The junction layer 66 is in direct contactwith all of the die pads 11 on which the semiconductor chips 41 aremounted. The metal layer 65 may have a region slightly out of the resinbottom surface 72. As shown in FIG. 16, part of the junction layer 66fills a region surrounded by the recess second side surface 755. Also,in the present embodiment, part of the junction layer 66 is between therecess support surfaces 756 and the metal layer 65.

The heat releasing layer 6 is for quickly releasing heat which wasgenerated in the semiconductor chip 41 to outside of the semiconductordevice 101B. In order to quickly release the heat generated by thesemiconductor chip 41 to outside of the semiconductor device 101B, theheat releasing layer 6 should be made of a material of a large thermalconductivity. While a larger thermal conductivity is preferred, therecan be a potential problem that the metal layer 65 will peel off, if theheat releasing layer's thermal expansion coefficient differs greatlyfrom that of the sealing resin portion 7. Preferably, therefore, theheat releasing layer 6 is of a material which has a larger thermalconductivity than that of a material which constitutes the sealing resinportion 7, and a similar thermal expansion coefficient to that of thematerial which constitutes the sealing resin portion 7. The heatreleasing layer 6 is faced directly to all of the die pads 11. As shownin FIG. 14, the heat releasing layer 6 covers all of the die pads 11entirely in xy plane view (i.e., as viewed in the thickness direction ofthe heat releasing layer 6).

As shown in FIG. 14 and FIG. 15, the heat releasing layer 6 has a heatreleasing layer main surface 61 and a heat releasing layer rear surface62. The heat releasing layer main surface 61 faces in the direction z1.The heat releasing layer main surface 61 covers the die pad rearsurfaces 112 and the recess bottom surfaces 751 of all of the die pads11 in xy-plane view. The heat releasing layer main surface 61 is indirect contact with the die pad rear surface 112 and the recess bottomsurface 751. The heat releasing layer rear surface 62 faces in thedirection z2 which is a direction opposite to the direction in which theheat releasing layer main surface 61 faces. The heat releasing layerrear surface 62 is not covered by the sealing resin portion 7 and isexposed from the sealing resin portion 7.

Next, a method of making the semiconductor device 101B will bedescribed. Drawings for describing the method will use the samereference symbols as those used thus far in identifying those describedthus far.

First, as shown in FIG. 17, a lead frame 300 which includes a pluralityof die pads 11, 31; and a plurality of semiconductor chips 41, 42 andpassive component chips 43 is prepared. Next, as shown in the drawing,each of the semiconductor chips 41 is disposed on one of the die pads 11via the junction layer (not illustrated). Likewise, each of thesemiconductor chip 42 and the passive component chips 43 is disposed onone of the control die pads 31 via the junction layer (not illustrated).Next, as shown in the drawing, a wire 8 is bonded to each of thesemiconductor chips 41, 42 and other components.

Next, as shown in FIG. 18 and FIG. 19, a sealing resin portion 7 isformed. As shown in FIG. 18, the formation of the sealing resin portion7 is performed by means of a molding method using a metal mold 881. Asshown in the drawing, the die pads 11 and other components are heldinside the metal mold 881. Next, a resin material is injected into themetal mold 881, and then the resin material is allowed to set. Once theresin material is set, the metal mold 881 is taken away from the diepads 11 and other components as shown in FIG. 19. Thus, the sealingresin portion 7 is formed. In the steps of forming the sealing resinportion 7, a recess 75 is formed in the sealing resin portion 7 forexposure of the die pads 11.

Next, as shown in FIG. 20, a heat releasing layer 6 is fitted into therecess 75 of the sealing resin portion 7. Then, pressure and vibrationare applied to the heat releasing layer 6. The heat releasing layer 6may be heated, in addition. The pressure, vibration and heat soften thejunction layer 66 of the heat releasing layer 6. The softened junctionlayer 66 moves within the recess 75, with part thereof filling a regionsurrounded by the recess second side surfaces 755. Also, part of thejunction layer 66 moves into a space between the recess support surface756 and the metal layer 65.

Next, the lead frame 300 shown in FIG. 17 is appropriately cut tocomplete the manufacture of the semiconductor devices 101B which isillustrated in FIG. 13, etc.

Next, functions of the present embodiment will be described.

According to the semiconductor device 101B, the metal layer 65 issupported at least indirectly by the recess support surfaces 756.Therefore, it is possible to prevent such a problem that the metal layer65 will become unduly slanted with respect to the resin bottom surface72 or become receded. Therefore, it is possible to reduce cases wherethe junction layer 66 overflows to outside of the metal layer 65 tocause a gap to be made between the metal layer 65 and the heat releasingmember 808. Thus, it is possible to increase heat release from thesemiconductor chips 41, 42, and to decrease separation of the metallayer.

By providing the junction layer 66 between the metal layer 65 and therecess support surfaces 756, it becomes possible to reliably fix themetal layer 65 to the sealing resin portion 7. If the junction layer 66has any end regions not covered by the metal layer 65, such a region canbe a place where the metal layer 65 will start to come off. Such alikelihood is low according to the present embodiment.

FIG. 21 and FIG. 22 show a semiconductor device according to Embodiment2B of the present invention. In these figures, elements identical withor similar to those in the previous embodiment described above areindicated by the same reference symbols as in the previous embodiment. Asemiconductor device 102B according to the present embodiment differsfrom the semiconductor device 101B in terms of the recess 75.

In the present embodiment, the recess 75 has a plurality of recess firstside surfaces 754, recess second side surfaces 755, and recess supportsurfaces 756, and further, a plurality of recess side surfaces 752 andrecess grooves 753. As shown in FIG. 21, the recess grooves 753, and therecess first side surfaces 754, the recess second side surfaces 755 andthe recess support surfaces 756 are disposed alternatingly along anouter edge of the recess 75. The recess first side surfaces 754, therecess second side surfaces 755 and the recess support surfaces 756 aredisposed at four corner regions of the recess 75.

As shown in FIG. 22, the recess groove 753 is between the recess bottomsurface 751 and the recess side surface 752, and in the presentembodiment, is disposed in a rectangular-annular pattern along an outeredge of the recess 75 as viewed in the z direction. As shown in FIG. 22,the recess groove 753 recedes from the recess bottom surface 751 in a z1direction. In the present embodiment, the recess groove 753 is slantedin such a manner that as it goes away from the recess bottom surface 751in the x direction, it also goes away from the surface 751 in the z1direction. The recess groove 753 has a maximum depth of approximately 50μm for example.

In the present embodiment, part of the junction layer 66 fills therecess groove 753. Also, the heat releasing layer 66 is in contact withthe recess side surface 752.

According to the semiconductor device 102B, in addition to thoseadvantages provided by the semiconductor device 101B, part of thejunction layer 66 fills the recess groove 753. To the extent the grooveis filled, it is possible to prevent the junction layer 66 from flowingover the recess 75 in the manufacturing step of the semiconductor device101B. Therefore, it is possible to prevent a gap from being made betweenthe heat releasing layer 6 and the heat releasing member 808 which istightly fitted thereto, and efficiently release heat which comes fromthe semiconductor chips 41, 42.

By disposing the recess groove 753 on an outer side of the metal layer65, it becomes possible to prevent an unintended gap from being madebetween the metal layer 65 and the recess groove 753. Eliminating thegap is suitable for increasing heat release.

By shaping the recess groove 753 into a taper, it becomes possible toreduce the area of the recess groove 753 which overlaps the metal layer65 as viewed in the z direction even if there is some misalignment inthe x direction or in the y direction when positioning the metal layer65. This preferable in eliminating the gap described above.

The present invention is not limited to the Embodiments described above.The present invention may be varied in many ways in any specificdetails. For example, as far as the metal layer is exposed from thesealing resin rear surface, the semiconductor device may not necessarilybe of an insertion mounting type but may have terminals for surfacemounting. Also, the invention is applicable not only to IPM devicesmentioned earlier but also to a semiconductor device which includes onlyone semiconductor chip and an island, but has a metal layer exposed froma rear surface of a sealing resin.

(Appendix 1) A semiconductor device comprising: a die pad having a mainsurface and a rear surface facing in opposite directions; asemiconductor chip mounted on the main surface of the die pad; a sealingresin portion which is formed with a recess receding from a resin bottomsurface, exposes the rear surface of the die pad yet covers the die padand the semiconductor chip; and a heat releasing layer disposed in therecess; wherein the recess has: a first side surface which is positionedon an outer side than is the die pad in a direction in which the rearsurface extends, and is connected to the resin bottom surface; a supportsurface which is connected to the first side surface and faces in adirection in which the rear surface faces; and a second side surfacewhich is connected to the support surface and is between the die pad andthe first side surface in the direction in which the rear surfaceextends whereas the heat releasing layer includes: a heat releasinglayer which has an outer edge with at least part thereof located betweenthe first side surface and the second side surface in the direction inwhich the rear surface extends, and overlaps the first side surface in athickness direction of the die pad; and a junction layer between theheat releasing layer and the die pad. (Appendix 2) The semiconductordevice according to Appendix 1, wherein the heat releasing layer is madeof a metal. (Appendix 3) The semiconductor device according to Appendix2, wherein the metal is provided by Cu. (Appendix 4) The semiconductordevice according to Appendix 2 or 3, wherein the junction layer is madeof a resin. (Appendix 5) The semiconductor device according to Appendix4, wherein part of the junction layer is between the support surface andthe heat releasing layer. (Appendix 6) The semiconductor deviceaccording to one of Appendices 1 through 5, wherein the recess has agroove which is positioned on an outer side than is the die pad in thedirection in which the rear surface extends, and has a region located ona side closer to the main surface than to the rear surface whereas thejunction layer has its part filling the groove. (Appendix 7) Thesemiconductor device according to Appendix 6, wherein the heat releasinglayer partially protrudes in its thickness direction, from the recess.(Appendix 8) The semiconductor device according to Appendix 6 or 7,wherein the groove is on an outer side with respect to the heatreleasing layer in the direction in which the rear surface extends.(Appendix 9) The semiconductor device according to Appendix 8, whereinthe recess includes a recess bottom surface which has a region betweenthe heat releasing layer and the groove. (Appendix 10) The semiconductordevice according to one of Appendices 6 through 9, wherein the groove isslanted in such a manner that as it goes away from the die pad in thedirection in which the rear surface extends, it comes closer from therear surface side to the main surface side in the thickness direction ofthe die pad. (Appendix 11) A semiconductor device comprising: aplurality of die pads each having a main surface and a rear surfacefacing in opposite directions; a plurality of semiconductor chips eachmounted on the main surface of one of the die pads; a sealing resinportion which is formed with a recess receding from a resin bottomsurface, commonly exposes the rear surfaces of at least one or more ofthe die pads yet commonly covers the die pads and the semiconductorchips; and a heat releasing layer disposed in the recess; wherein therecess, on its side facing the rear surface, has: a first side surfacewhich is on an outer side than is any of the die pads and is connectedto the resin bottom surface; a support surface which is connected to thefirst side surface and faces in a direction in which the rear surfacefaces; and a second side surface which is connected to the supportsurface and is between the die pad and the first side surface in adirection in which the rear surface extends whereas the heat releasinglayer includes: a heat releasing layer which has an outer edge with atleast part thereof being between the first side surface and the secondside surface in the direction in which the rear surface extends, andoverlaps the first side surface in a thickness direction of the die pad;and a junction layer positioned between the heat releasing layer and thedie pad.

FIG. 23 is a sectional view showing a packaging structure when use ismade of a semiconductor device according to Embodiment 1C of the presentinvention.

A semiconductor device packaging structure 801 shown in FIG. 23 includesa semiconductor device 101C, a substrate 807 and a heat releasing member808.

The substrate 807 is capable of having a plurality of electriccomponents mounted thereon. The substrate 807 is made of an insulatingmaterial. The substrate 807 is formed with an unillustrated wiringpattern. The substrate 807 is formed with a plurality of holes 809. Theheat releasing member 808 is made of a material which has a relativelyhigh heat conductivity like a metal such as aluminum. The heat releasingmember 808 is fixed to the substrate 807 by an unillustrated supportingmember. The semiconductor device 101C is mounted on the substrate 807.In the present embodiment, the semiconductor device 101C is a so calledIPM (Intelligent Power Module) product. The semiconductor device 101C isused for such an application as electric power source control in an airconditioner, a motor controller, etc.

FIG. 24 is a plan view (partially unillustrated) of the semiconductordevice according to Embodiment 1C of the present invention, before leadsare bent. FIG. 25 is a bottom view of the semiconductor device accordingto Embodiment 1C of the present invention, before the leads are bent.FIG. 26 is a sectional view taken in lines IIVI-IIVI in FIG. 24. FIG. 27is an enlarged sectional view of a primary portion taken from FIG. 26.FIG. 23 represents a section taken in lines XXIII-XXIII in FIG. 24. InFIG. 26, each component is illustrated schematically for easiercomprehension.

The semiconductor device 101C shown in these drawings includes aplurality of first electrode portions 1, second electrode portions 2 andthird electrode portions 3; a plurality of semiconductor chips 41, 42;passive component chips 43; a heat releasing layer 6; a sealing resinportion 7 and wires 8. FIG. 24 shows the heat releasing layer 6 inbroken lines and the sealing resin portion 7 in imaginary lines.

The sealing resin portion 7 covers the plurality of the first electrodeportions 1, the second electrode portions 2, and the third electrodeportions 3; the semiconductor chips 41, 42; and the passive componentchips 43. The sealing resin portion 7 is made of a black epoxy resin forexample. As shown in FIG. 25 and FIG. 26, the sealing resin portion 7has a resin main surface 71, a resin bottom surface 72 and a resin sidesurface 73.

The resin main surface 71 is a flat surface which faces in a directionz1 and extends along an xy plane. The resin bottom surface 72 is a flatsurface which faces in a direction z2 that is opposite to the directionz1 and extends along xy plane. The resin side surface 73 surrounds thesemiconductor chips 41, 42 and the passive component chips 43 inxy-plane view. The resin side surface 73 is connected to the resin mainsurface 71 and the resin bottom surface 72.

As clearly shown in FIG. 26, the sealing resin portion 7 is formed witha recess 75. The recess 75 recedes from the resin bottom surface 72. Therecess 75 has a recess bottom surface 751. The recess bottom surface 751extends along an xy plane.

As shown in FIG. 24, the semiconductor chips 41, 42 and the passivecomponent chips 43 are rectangular in plan view. The semiconductor chip41 is a power chip such as an IGBT, MOS, and diode. The semiconductorchip 42 is an LSI chip such as a control IC. The passive component chips43 are, for example, resisters, capacitors or other passive components.

The first electrode portions 1, the second electrode portions 2 and thethird electrode portions 3 in FIG. 24 are all made of an electricallyconductive material. An example of such an electrically conductivematerial is copper. The electrode portion shown in a bottom right regionin FIG. 24 is grounded.

Each of the plurality (four, in the present embodiment) of the firstelectrode portions 1 includes a die pad 11 (see FIG. 23, FIG. 24 andFIG. 26), a connecting region 12 (see FIG. 23 and FIG. 24), a wirebonding region 13 (see FIG. 23 and FIG. 24) and a lead 14 (see FIG. 23through FIG. 25). The first electrode portions 1 are spaced from eachother in the direction x.

Each die pad 11 is a flat plate extending along and parallel to an xyplane. The semiconductor chip 41 is disposed on the die pad 11. As shownin FIG. 26, a junction layer 991 is between the die pad 11 and thesemiconductor chip 41. The junction layer 991 is made of an electricallyconductive material. The electrically conductive material is provided bysolder or silver paste, for example. Solder has a relatively largethermal conductivity. Use of solder as the junction layer 991 enablesefficient heat conduction from the semiconductor chip 41 to the die pad11. Each of the die pads 11 is exposed from the recess bottom surface751.

Each die pad 11 has a die pad main surface 111 and a die pad rearsurface 112. The die pad main surface 111 faces in the direction z1whereas the die pad rear surface 112 faces in the direction z2. In otherwords, the die pad main surface 111 and the die pad rear surface 112 arearranged to face in the mutually opposite directions. The semiconductorchip 41 is disposed on the die pad main surface 111. A junction layer991 is between the die pad main surface 111 and the semiconductor chip41. The die pad rear surface 112 is located at the same position as therecess bottom surface 751 in a thickness direction (the direction z) ofthe die pad 11. However, the die pad rear surface 112 may be closer toan opening of the recess 75 than is the recess bottom surface 751.

As shown in FIG. 24, each connecting region 12 is disposed between thedie pad 11 and the wire bonding region 13, and connected to the die pad11 and to the wire bonding region 13. As shown in FIG. 23, theconnecting region 12 extends along a plane which is inclined withrespect to an xy plane. The connecting region 12 is inclined withrespect to an xy plane in such a manner that it goes farther in thedirection z1 as it is further away from the die pad 11.

Each wire bonding region 13 shown in FIG. 23 and FIG. 24 extends alongan xy plane. In the direction z, each wire bonding region 13 is on aside more toward the direction z1 than is the die pad 11. A wire 8 isbonded to one of the wire bonding regions 13 and to one of thesemiconductor chips 41. Thus, electrical conductivity is establishedbetween said one of the wire bonding regions 13 and said one of thesemiconductor chips 41. The leads 14 are connected to the wire bondingregions 13. Each lead 14 extends along the direction y. The lead 14 hasa portion extending out of the resin side surface 73 of the sealingresin portion 7. In the present embodiment, the leads 14 are forinsertion mounting. As shown in FIG. 23, when mounting the semiconductordevice 101C on the substrate 807, the leads 14 are bent and insertedthrough the holes 809. For fixing the leads 14 in the substrate 807, theholes 809 are filled with solder layers 810.

As shown in FIG. 24, each of the plurality (three, in the presentembodiment) of the second electrode portions 2 includes a wire bondingregion 23 and a lead 24. The second electrode portions 2 are spaced fromeach other in the direction x.

Each wire bonding region 23 extends along an xy plane. In the directionz, each wire bonding region 23 is on a side more toward the direction z1than is the die pad 11. A wire 8 is bonded to one of the wire bondingregions 23 and to one of the semiconductor chips 41. Thus, electricalconductivity is established between said one of the wire bonding regions23 and said one of the semiconductor chips 41. The leads 24 areconnected to the wire bonding regions 23. Each lead 24 extends along thedirection y. The lead 24 has a portion extending out of the resin sidesurface 73 of the sealing resin portion 7. In the present embodiment,the leads 24 are for insertion mounting. Though not illustrated, whenmounting the semiconductor device 101C on the substrate 807, the leads24 are bent and inserted through the holes 809 like the leads 14.

The third electrode portions 3 shown in FIG. 23, FIG. 24 includes aplurality of control die pads 31 and a plurality of leads 32. Thecontrol die pads 31 and the leads 32 are respectively disposed at thesame positions in the direction z. On each control die pad 31, thesemiconductor chip 42 or the passive component chips 43 is disposed. Ajunction layer (not illustrated) is formed between the control die pad31 and the semiconductor chip 42, and between the control die pads 31and the passive component chips 43. The control die pads 31 need nothave its rear surface faced to the heat releasing layer 6 or exposed.

Each lead 32 has a portion extending out of the resin side surface 73 ofthe sealing resin portion 7. In the present embodiment, the leads 32 arefor insertion mounting. As shown in FIG. 23, when mounting thesemiconductor device 101B on the substrate 807, the leads 32 are bentand inserted through the holes 809. As has been described in relationwith the leads 14, the holes 809 are filled with solder layers 810 forfixing the leads 32 in the substrate 809. A wire 8 is bonded to one ofthe leads 32 and to one of the semiconductor chips 42. Thus, electricalconductivity is established between said one of the leads 32 and saidone of the semiconductor chips 42. Also, a wire 8 is bonded to one ofthe semiconductor chip 42 and to one of the passive component chips 43.It should be noted here that wires used for the controllingsemiconductor chip 42 or the passive component chips 43 are oftenprovided by fine wires made of aluminum or gold which are finer andsofter than the wire 8.

As shown in FIG. 26, the heat releasing layer 6 is in the recess 75 inthe sealing resin portion 7. In the present embodiment, the heatreleasing layer 6 is a flat plate extending along and parallel to an xyplane. In the present embodiment, the heat releasing layer 6 is made ofceramics, Cu or aluminum. The heat releasing layer 6 has a heatreleasing layer main surface 61, a heat releasing layer rear surface 62,a first side surface 631, an intermediate surface 632, and a second sidesurface 633.

The heat releasing layer main surface 61 faces in the direction z1. Theheat releasing layer main surface 61 covers the die pad rear surfaces112 and the recess bottom surfaces 751 of all of the die pads 11 inxy-plane view. The heat releasing layer rear surface 62 faces in thedirection z2 which is a direction opposite to the direction in which theheat releasing layer main surface 61 faces. The heat releasing layerrear surface 62 is not covered by the sealing resin portion 7 and isexposed from the sealing resin portion 7. The heat releasing layer mainsurface 61 of the heat releasing layer 6 is joined to the die pad rearsurface 112 of a plurality of the die pads 11 by the junction layer 69.The junction layer 69 is made of a resin for example.

As shown in FIG. 26 and FIG. 27, the first side surface 631 is connectedto the heat releasing layer rear surface 62 and extends substantially ina direction z. The first side surface 631 is on an outside of the diepad 11 as viewed in the z direction. The second side surface 633 isconnected to heat releasing layer main surface 61 and extendssubstantially in the direction z. The second side surface 633 is betweenthe die pad 11 and the first side surface 754 as viewed in the zdirection. The intermediate surface 632 connects the first side surface631 and the second side surface 633 with each other and facessubstantially a direction z2. In order to make sure that the presentinvention provides its intended function, it is preferable that adimension of the first side surface 631 in the direction z is greaterthan a dimension of the second side surface 633 in the direction z.

All of the first side surface 631, the intermediate surface 632 and thesecond side surface 633 are in contact with the sealing resin portion 7.Also, the heat releasing layer rear surface 62 is flush with the resinbottom surface 72 of the sealing resin portion 7. Also, as shown in FIG.27, the first side surface 631 and the intermediate surface 632constitute a first angled region 634. The intermediate surface 632 andthe second side surface 633 constitute a second angled region 645. Inthe present embodiment, both the first angled region 634 and the secondangled region 645 have a square angle. However, they may be chamfered.

The heat releasing layer 6 is for quickly releasing heat which wasgenerated in the semiconductor chip 41 to outside of the semiconductordevice 101C. In order to achieve this goal, it is preferable that theheat releasing layer 6 is made of a material which has as large thermalconductivity as possible; however, if the heat releasing layer's thermalexpansion coefficient differs greatly from that of the sealing resinportion 7, there can be a potential problem that the metal layer 6 willpeel off. Preferably, therefore, the heat releasing layer 6 is of amaterial which has a larger thermal conductivity than that of a materialwhich constitutes the sealing resin portion 7, and a similar thermalexpansion coefficient to that of the material which constitutes thesealing resin portion 7. The heat releasing layer 6 is faced directly toall of the die pads 11. As shown in FIG. 25, the heat releasing layer 6covers all of the die pads 11 entirely in xy plane view (i.e., as viewedin the thickness direction of the heat releasing layer 6).

Next, a method of making the semiconductor device 101C will bedescribed. Drawings for describing the method will use the samereference symbols as those used thus far in identifying those describedthus far.

First, as shown in FIG. 28, a lead frame 300 which includes a pluralityof die pads 11, 31; and a plurality of semiconductor chips 41, 42 andpassive component chips 43 is prepared. Next, as shown in the drawing,each of the semiconductor chips 41 is disposed on one of the die pads 11via the junction layer (not illustrated). Likewise, each of thesemiconductor chip 42 and the passive component chips 43 is disposed onone of the control die pads 31 via the junction layer (not illustrated).Next, as shown in the drawing, a wire 8 is bonded to each of thesemiconductor chips 41, 42 and other components.

Next, as shown in FIG. 29, a sealing resin portion 7 is formed. Beforethe formation of the sealing resin portion 7, the heat releasing layer 6is joined to the die pads 11 by the junction layer 69. The heatreleasing layer 6 is formed, for example, by preparing a flatplate-shaped material of ceramic and making a groove of a certain widthin the material plate using a dicing blade. Next, using a narrower bladethan the previous one, the material plate is divided in a manner suchthat the above-mentioned groove is split along its center. By thesesteps, the heat releasing layer 6 having the first side surface 631, theintermediate surface 632 and the second side surface 633 is obtained.

The formation of the sealing resin portion 7 is performed by means of amolding method using a metal mold 881. As shown in FIG. 29, the heatreleasing layer 6 and other components are pressed by the metal mold881. Next, a resin material is injected into the metal mold 881, andthen the resin material is allowed to set. Once the resin material sets,a sealing resin portion 7 is complete.

Next, the lead frame 300 shown in FIG. 28 is appropriately cut tocomplete the manufacture of the semiconductor device 101C which isillustrated in FIG. 24, etc.

Next, functions of the present embodiment will be described.

According to the semiconductor device 101C, even if there occurs aseparation between the heat releasing layer 6 and the resin bottomsurface 72, the growth of the separation will be limited within thefirst side surface 631 and will not continue into the intermediatesurface 632 or further. Therefore, even if a separation has occurred, atleast the second side surface 633 can play its part in providing ajunction between the heat releasing layer 6 and the sealing resinportion 7. Therefore, it is possible to reduce such a case that a gapbecomes excessively big between the heat releasing layer 6 and thesealing resin portion 7, to reach the heat releasing layer main surface61.

The square-angled first angled region 634 is suitable in blocking thegrowth of separation. Further, by forming the square-angled secondangled region 645 at a deeper position than the first angled region 634,it becomes possible to block the growth of a gap more reliably.

The first side surface 631 has a dimension (depth) in the direction zwhich is greater than a dimension (depth) in the direction z of thesecond side surface 633. This contributes in controlling a separationnot to easily reach the intermediate surface 632, adding an advantage topreventing the separation from growing.

FIG. 30 and FIG. 31 show a semiconductor device according to Embodiment2C of the present invention. In these figures, elements identical withor similar to those in the previous embodiment are indicated by the samereference codes as in the previous embodiment. A semiconductor device102C according to the present embodiment differs from the semiconductordevice 101C in terms of the heat releasing layer 6.

In the present embodiment, the heat releasing layer 6 has a plurality ofgrooves 611. The grooves 611 are formed in the heat releasing layer mainsurface 61. The grooves 611 extend in the y direction, and are disposedat an equal space to each other. Each groove 611 has a rectangularsection. Some of the grooves 611 are filled with part of the junctionlayer 69. Also, some of the grooves 611 are filled with part of thesealing resin portion 7.

The grooves 611 are formed in the above-noted step of forming the heatreleasing layer 6. Specifically, before dividing the material plate, aplurality of mutually parallel grooves are formed in the material plateby using mutually parallel blades or by laser. These grooves are to bethe grooves 611 in the heat releasing layer 6.

The semiconductor device 102C provides functions which are provided bythe semiconductor device 101C. Also, the grooves 611 are formed inaddition, and so the grooves 611 are filled with part of the junctionlayer 69 and part of the sealing resin portion 7. This will provide a socalled anchoring effect, i.e., improved bonding strength between theheat releasing layer 6 and the junction layer 69 and improved bondingstrength between the heat releasing layer 6 and the sealing resinportion 7. The grooves 611 which have a rectangular section workssuitably for increasing the anchoring effect.

The present invention is not limited to the Embodiments described above.The present invention may be varied in many ways in any specificdetails. For example, as far as the heat releasing layer is exposed fromthe sealing resin rear surface, the semiconductor device may notnecessarily be of an insertion mounting type but may have terminals forsurface mounting. Also, the invention is applicable not only to IPMdevices mentioned earlier but also to a semiconductor device whichincludes only one semiconductor chip and an island, but has a heatreleasing layer exposed from a rear surface of a sealing resin.

(Appendix 1) A semiconductor device comprising: a die pad having a diepad main surface and a die pad rear surface facing in oppositedirections; a semiconductor chip mounted on the die pad main surface; asealing resin portion which is formed with a recess receding from abottom surface, exposes the die pad rear surface yet covers the die padand the semiconductor chip; and a heat releasing layer which is disposedin the recess, has a heat releasing layer main surface facing the diepad rear surface and a heat releasing layer rear surface facing awayfrom the heat releasing layer main surface, and is joined to the diepad; wherein the heat releasing layer has: a first side surface which ispositioned on an outer side than is the die pad in a direction in whichthe die pad rear surface extends, and is connected to the heat releasinglayer rear surface; an intermediate surface which is connected to thefirst side surface and faces in a direction in which the heat releasinglayer main surface faces; and a second side surface which is connectedto the intermediate surface and is between the die pad and the firstside surface in a direction in which the die pad rear surface extends.(Appendix 2) The semiconductor device according to Appendix 1, whereinthe heat releasing layer is made of a ceramic. (Appendix 3) Thesemiconductor device according to Appendix 1 or 2, wherein the firstside surface, the intermediate surface and the second side surface arein contact with the sealing resin portion. (Appendix 4) Thesemiconductor device according to Appendix 3, wherein the heat releasinglayer rear surface of the heat releasing layer is flush with the bottomsurface of the sealing resin portion. (Appendix 5) The semiconductordevice according to one of Appendices 1 through 4, wherein the firstside surface and the intermediate surface form a first angled region.(Appendix 6) The semiconductor device according to one of Appendices 1through 5, wherein the intermediate surface and the second side surfaceform a second angled region. (Appendix 7) The semiconductor deviceaccording to Appendix 6, wherein at least one of the first angled regionand the second angled region has a right angle. (Appendix 8) Thesemiconductor device according to one of Appendices 1 through 7, whereinthe first side surface has a greater dimension in a thickness directionof the heat releasing layer than a dimension of the second side surfacein the thickness direction of the heat releasing layer. (Appendix 9) Thesemiconductor device according to one of Appendices 1 through 8, whereinthe heat releasing layer and the die pad are joined to each other by ajunction layer. (Appendix 10) The semiconductor device according toAppendix 9, wherein the heat releasing layer main surface of the heatreleasing layer is formed with a plurality of grooves extending in adirection perpendicular to a thickness direction of the heat releasinglayer. (Appendix 11) The semiconductor device according to Appendix 10,wherein each of the grooves has a rectangular section. (Appendix 12) Thesemiconductor device according to Appendix 10 or 11, wherein one or moreof the grooves are in contact with the junction layer. (Appendix 13) Thesemiconductor device according to one of Appendices 10 through 12,wherein some of the grooves are in contact with the sealing resinportion. (Appendix 14) A semiconductor device comprising: a plurality ofdie pads each having a die pad main surface and a die pad rear surfacefacing in opposite directions; a plurality of semiconductor chips eachmounted on one of the die pad main surfaces; a sealing resin portionwhich is formed with a recess receding from a bottom surface, commonlyexposes the die pad rear surfaces yet commonly covers each die pad andeach semiconductor chip and; and a heat releasing layer which isdisposed in the recess, has a heat releasing layer main surface facingthe die pad rear surfaces and a heat releasing layer rear surface facingaway from the heat releasing layer main surface, and is commonly joinedwith each die pad; wherein the heat releasing layer has: a first sidesurface which is positioned on an outer side than is the die pad in adirection in which the die pad rear surface extends, and is connected tothe heat releasing layer rear surface; an intermediate surface which isconnected to the first side surface and faces in a direction in whichthe heat releasing layer main surface faces; and a second side surfacewhich is connected to the intermediate surface and is between the diepad and the first side surface in the direction in which the die padrear surface extends.

FIG. 32 is a sectional view showing a packaging structure when use ismade of a semiconductor device according to Embodiment 1D of the presentinvention.

A semiconductor device packaging structure 801 shown in FIG. 32 includesa semiconductor device 101D, a substrate 807 and a heat releasing member808.

The substrate 807 is capable of having a plurality of electriccomponents mounted thereon. The substrate 807 is made of an insulatingmaterial. The substrate 807 is formed with an unillustrated wiringpattern. The substrate 807 is formed with a plurality of holes 809. Theheat releasing member 808 is made of a material which has a relativelyhigh heat conductivity like a metal such as aluminum. The heat releasingmember 808 is fixed to the substrate 807 by an unillustrated supportingmember. The semiconductor device 101D is mounted on the substrate 807.In the present embodiment, the semiconductor device 101D is a so calledIPM (Intelligent Power Module) product. The semiconductor device 101D isused for such an application as electric power source control in an airconditioner, a motor controller, etc.

FIG. 33 and FIG. 34 are plan views (partially unillustrated) of thesemiconductor device according to Embodiment 1D of the presentinvention, before leads are bent. FIG. 35 is a bottom view of thesemiconductor device according to Embodiment 1D of the presentinvention, before the leads are bent. FIG. 36 is a sectional view takenin lines XXXVI-XXXVI in FIG. 33. FIG. 32 represents a section taken inlines XXXII-XXXII in FIG. 33. In FIG. 36, each component is illustratedschematically for easier comprehension.

The semiconductor device 101D shown in these drawings includes aplurality of first electrode portions 1, second electrode portions 2 andthird electrode portions 3; a plurality of semiconductor chips 41, 42;passive component chips 43; a heat releasing layer 6; a sealing resinportion 7 and wires 8. FIG. 33 shows the heat releasing layer 6 inbroken lines and the sealing resin portion 7 in imaginary lines.

The sealing resin portion 7 covers the plurality of the first electrodeportions 1, the second electrode portions 2, and the third electrodeportions 3; the semiconductor chips 41, 42; and the passive componentchips 43. The sealing resin portion 7 is made of a black epoxy resin forexample. As shown in FIG. 35 and FIG. 36, the sealing resin portion 7has a resin main surface 71, a resin bottom surface 72 and a resin sidesurface 73.

The resin main surface 71 is a flat surface which faces in a directionz1 and extends along an xy plane. The resin bottom surface 72 is a flatsurface which faces in a direction z2 that is opposite to the directionz1 and extends along the xy plane. The resin side surface 73 surroundsthe semiconductor chips 41, 42 and the passive component chips 43 inxy-plane view. The resin side surface 73 is connected to the resin mainsurface 71 and the resin bottom surface 72.

As clearly shown in FIG. 36, the sealing resin portion 7 is formed witha recess 75. The recess 75 recedes from the resin bottom surface 72. Therecess 75 has a recess bottom surface 751 and a recess side surface 752.The recess bottom surface 751 extends along an xy plane. The recess sidesurface 752 is connected to the resin bottom surface 72. The recess sidesurface 752 extends substantially in a direction z.

As shown in FIG. 33, the semiconductor chips 41, 42 and the passivecomponent chips 43 are rectangular in plan view. The semiconductor chip41 is a power chip such as an IGBT, MOS and diode, or an outputtransistor. The semiconductor chip 42 is an LSI chip such as a controlIC, or controls the semiconductor chip 41. The passive component chips43 are, for example, resisters, capacitors or other passive components.The semiconductor chip 41 has electrodes 411. The semiconductor chip 42also has electrodes which are similar to the electrodes 411. Thefollowing description of the electrodes 411 also applies to theseelectrodes.

The first electrode portions 1, the second electrode portions 2 and thethird electrode portions 3 in FIG. 33 are all made of an electricallyconductive material. An example of such an electrically conductivematerial is copper. The electrode portion shown in a bottom right regionin FIG. 33 is grounded.

Each of the plurality (four, in the present embodiment) of the firstelectrode portions 1 includes a die pad 11 (see FIG. 32 through FIG. 34and FIG. 36), a connecting region 12 (see FIG. 32 through FIG. 34), awire bonding region 13 (see FIG. 32 through FIG. 34) and a lead 14 (seeFIG. 32 through FIG. 35). The first electrode portions 1 are spaced fromeach other in the direction x.

Each die pad 11 is a flat plate extending along and parallel to an xyplane. The semiconductor chip 41 is disposed on the die pad 11. As shownin FIG. 36, a junction layer 991 is between the die pad 11 and thesemiconductor chip 41. The junction layer 991 is made of an electricallyconductive material. The electrically conductive material is provided bysolder or silver paste, for example. Solder has a relatively largethermal conductivity. Use of solder as the junction layer 991 enablesefficient heat conduction from the semiconductor chip 41 to the die pad11. Each of the die pads 11 is exposed from the recess bottom surface751.

Each die pad 11 has a die pad main surface 111 and a die pad rearsurface 112. The die pad main surface 111 faces in the direction z1whereas the die pad rear surface 112 faces in the direction z2. In otherwords, the die pad main surface 111 and the die pad rear surface 112 arearranged to face in the mutually opposite directions. The semiconductorchip 41 is disposed on the die pad main surface 111. A junction layer991 is between the die pad main surface 111 and the semiconductor chip41. The die pad rear surface 112 is located at the same position as therecess bottom surface 751 in a thickness direction (the direction z) ofthe die pad 11. However, the die pad rear surface 112 may be closer toan opening of the recess 75 than is the recess bottom surface 751.

As shown in FIG. 33, each connecting region 12 is disposed between thedie pad 11 and the wire bonding region 13, and connected to the die pad11 and to the wire bonding region 13. As shown in FIG. 32, theconnecting region 12 extends along a plane which is inclined withrespect to an xy plane. The connecting region 12 is inclined withrespect to an xy plane in such a manner that it goes farther in thedirection z1 as it is further away from the die pad 11.

Each wire bonding region 13 shown in FIG. 32 through FIG. 34 extendsalong an xy plane. In the direction z, each wire bonding region 13 is ona side more toward the direction z1 than is the die pad 11. A wire 8 isbonded to one of the wire bonding regions 13 and to one of thesemiconductor chips 41. Thus, electrical conductivity is establishedbetween said one of the wire bonding regions 13 and said one of thesemiconductor chips 41. The leads 14 are connected to the wire bondingregions 13. Each lead 14 extends along the direction y. The lead 14 hasa portion extending out of the resin side surface 73 of the sealingresin portion 7. In the present embodiment, the leads 14 are forinsertion mounting. As shown in FIG. 32, when mounting the semiconductordevice 101D on the substrate 807, the leads 14 are bent and insertedthrough the holes 809. For fixing the leads 14 in the substrate 807, theholes 809 are filled with solder layers 810. The wire 8 which isconnected to the semiconductor chip 41 and the wire bonding region 13 ismade of aluminum.

As shown in FIG. 34, the die pad 11 is formed with a pair of press marks113. The press marks 113 are formed during a bonding step of the wire 8which will be described later. The press marks 113 are slight recessesreceding from the die pad main surface 111 of the die pad 11, and looklike scars. In the present embodiment, the press marks 113 are spacedfrom each other in the direction x, sandwiching the semiconductor chip41. The semiconductor chip 41 is formed with three electrodes 411disposed inline in the direction x between the pair of press marks 113.Each wire 8 bonded to one of the electrodes 411 has a first bondingportion 81, which crosses a straight line connecting the press marks 113with each other.

The wire bonding region 13 is formed with a pair of press marks 131. Thepress marks 131 are formed during a bonding step of the wire 8 whichwill be described later. The press marks 131 are slight recesses fromthe surface of the wire bonding region 13, and look like scars. In thepresent embodiment, the press marks 131 are spaced from each other inthe direction x. The wire 8 bonded to the wire bonding region 13 has asecond bonding portion 82, which crosses a straight line connecting thepress marks 131 with each other. Press marks which are similar to thepress marks 131 formed in the wire bonding region 13 are formed in awire bonding region 23 which will be described later.

As shown in FIG. 33, each of the plurality (three, in the presentembodiment) of the second electrode portions 2 includes a wire bondingregion 23 and a lead 24. The second electrode portions 2 are spaced fromeach other in the direction x.

Each wire bonding region 23 extends along an xy plane. In the directionz, each wire bonding region 23 is on a side more toward the direction z1than is the die pad 11. A wire 8 is bonded to one of the wire bondingregions 23 and to one of the semiconductor chips 41. Thus, electricalconductivity is established between said one of the wire bonding regions23 and said one of the semiconductor chips 41. The leads 24 areconnected to the wire bonding regions 23. Each lead 24 extends in thedirection y. The lead 24 has a portion extending out of the resin sidesurface 73 of the sealing resin portion 7, receives the same steps asdoes the lead 14, and is inserted through the hole 809 in the substrate807. The wire 8 which is connected to the semiconductor chip 41 and thewire bonding region 23 is made of aluminum.

The third electrode portions 3 shown in FIG. 32, FIG. 33 includes aplurality of control die pads 31 and a plurality of leads 32. Thecontrol die pads 31 and the leads 32 are respectively disposed at thesame positions in the direction z.

On each control die pad 31, the semiconductor chip 42 or the passivecomponent chips 43 is disposed. A junction layer (not illustrated) isformed between the control die pad 31 and the semiconductor chip 42, andbetween the control die pads 31 and the passive component chips 43. Thecontrol die pads 31 need not have its rear surface faced to the heatreleasing layer 6 or exposed.

Each lead 32 has a portion extending out of the resin side surface 73 ofthe sealing resin portion 7, receives the same steps as does the lead14, and is inserted through the hole 809 in the substrate 807. A wire 8is bonded to one of the leads 32 and to a predetermined electrode of oneof the semiconductor chips 42. Thus, electrical conductivity isestablished between said one of the leads 32 and said one of thesemiconductor chips 42. Also, a wire 8 is bonded to a predeterminedelectrode of one of the semiconductor chips 42 and to one of the passivecomponent chips 43. It should be noted here that wires used for thecontrolling semiconductor chip 42 or the passive component chips 43 areoften provided by fine wires made of aluminum or gold which are finerand softer than the wire 8.

The heat releasing layer 6 is made of ceramics, Cu or aluminum, and isdisposed in the recess 75 in the sealing resin portion 7 as shown inFIG. 36. The heat releasing layer 6 is surrounded by the recess sidesurface 752. In the present embodiment, the heat releasing layer 6 is aflat plate extending along and parallel to an xy plane. In the presentembodiment, the heat releasing layer 6 is constituted by the metal layer65 and the junction layer 66. The metal layer 65 is on a side toward thez2 direction, and is made of Cu which has a thickness of approximately105 μm for example. The junction layer 66 is on a side toward the z1direction with respect to the metal layer 65 and joins the metal layer65 to the die pad rear surfaces 112 of the die pads 11. The junctionlayer 66 is made of an insulating resin for example, and has a thicknessof approximately 250 μm for example. The resin becomes soft when itreceives pressure and vibration in a manufacturing step of thesemiconductor device 101D and is in direct contact with all of the diepads 11 on which the semiconductor chips 41 are mounted. The metal layer65 may have a region (s) slightly out of the resin bottom surface 72.The junction layer 66 is in contact with the recess side surface 752.

The heat releasing layer 6 is for quickly releasing heat which wasgenerated in the semiconductor chip 41 to outside of the semiconductordevice 101D. In order to achieve this goal, it is preferable that theheat releasing layer 6 is made of a material which has as large thermalconductivity as possible. However, if the heat releasing layer's thermalexpansion coefficient differs greatly from that of the sealing resinportion 7, there can be a potential problem that the metal layer 6 willpeel off. Preferably, therefore, the heat releasing layer 6 is of amaterial which has a larger thermal conductivity than that of a materialwhich constitutes the sealing resin portion 7, and a similar thermalexpansion coefficient to that of the material which constitutes thesealing resin portion 7. The heat releasing layer 6 is faced directly toall of the die pads 11. As shown in FIG. 35, the heat releasing layer 6covers all of the die pads 11 entirely in xy plane view (i.e., as viewedin the thickness direction of the heat releasing layer 6).

As shown in FIG. 35 and FIG. 36, the heat releasing layer 6 has a heatreleasing layer main surface 61 and a heat releasing layer rear surface62. The heat releasing layer main surface 61 faces in the direction z1.The heat releasing layer main surface 61 covers the die pad rearsurfaces 112 and the recess bottom surfaces 751 of all of the die pads11 in xy-plane view. The heat releasing layer main surface 61 is indirect contact with the die pad rear surface 112 and the recess bottomsurface 751. The heat releasing layer rear surface 62 faces in thedirection z2 which is a direction opposite to the direction in which theheat releasing layer main surface 61 faces. The heat releasing layerrear surface 62 is not covered by the sealing resin portion 7 and isexposed from the sealing resin portion 7.

Next, a method of making of the semiconductor device 101D will bedescribed. Drawings for describing the method will use the samereference symbols as those used thus far in identifying those describedthus far.

First, as shown in FIG. 37, a lead frame 300 which includes a pluralityof die pads 11, 31; and a plurality of semiconductor chips 41, 42 andpassive component chips 43 is prepared. Next, as shown in the drawing,each of the semiconductor chips 41 is disposed on one of the die pads 11via the junction layer (not illustrated). Likewise, each of thesemiconductor chip 42 and the passive component chips 43 is disposed onone of the control die pads 31 via the junction layer (not illustrated).

Next, the bonding of wires 8 is performed. FIG. 38 shows an example ofbonding apparatus for bonding aluminum wires 8. The illustrated bondingapparatus 85 includes a capillary 851, a guide 852, a cutter 853, a base854, an arm 855, and a wire reel 856. A wire 8 is wound around the wirereel 856. The arm 855 is attached to the base 854 via a vibrationgenerator such as an ultrasonic wave generator. The wire 8 is unwoundfrom the wire reel 856 and fed along the guide 852 to the tip of thecapillary 851. The capillary 851 presses the wire 8 to a bonding objectwhile applying vibration (“wedge bonding”). Then, the bonded wire is cutby the cutter 853.

Hereinafter, reference will be made to FIG. 39 to describe steps ofbonding a wire to a semiconductor chip 41 which is mounted on a die pad11, with a wire bonding region 13 which is connected to an adjacent diepad 11. All the other wire bondings will be performed in the same way ifthe wire 8 is made of aluminum. Before the wire 8 is actually bonded, alead frame 300 is set into a jig for example. The jig 860 is formed tofollow the shape of the lead frame 300, and has support surfaces 861,862. The support surface 861 supports the die pad 11 while the supportsurface 862 support the wire bonding region 13.

Next, as shown in FIG. 40, a pair of pressing pieces 831 and a pair ofpressing pieces 832 are prepared. The pressing pieces 831 and thepressing pieces 832 are each provided by paired, fine, metal rods forexample. The pair of pressing pieces 831 are pressed onto the die pad11. During this process, the pair of pressing pieces 831 are separatedfrom each other in the direction x so that the pressing pieces 831sandwich three electrodes 411 of the semiconductor chip 41. Likewise,the pair of pressing pieces 832 are pressed onto the wire bonding region13. The pair of pressing pieces 832 are separated in the direction x.

Next, as shown in FIG. 41, a first bonding step of a wire 8 isperformed. The tip of the capillary 851 which holds a wire is broughtinto contact with an electrode 411 of the semiconductor chip 41. Then,pressure and ultrasonic vibration are applied from the capillary 851 tothe wire 8 whereby the wire 8 is bonded to the electrode 411.

Next, as shown in FIG. 42, a second bonding step of a wire 8 isperformed. The tip of the capillary 851 is moved from the electrode 411of the semiconductor chip 41 to the wire bonding region 13. Then,pressure and ultrasonic vibration are applied from the capillary 851 tothe wire 8 whereby the wire 8 is bonded to the wire bonding region 13.Also, after this bonding, the cutter 853 shown in FIG. 38 cuts the wire8.

By performing the first bonding step and the second bonding stepdescribed above, wires 8 as shown in FIG. 43 and FIG. 44 are obtained;i.e., one wire is bonded at the first bonding portion 81 to theelectrode 411 of the semiconductor chip 41 while the other wire isbonded at the second bonding portion 82 to the wire bonding region 13.As shown in FIG. 44, places in the die pad 11 where the pair of pressingpieces 831 were pressed onto are formed with a pair of press marks 113.Also, places in the wire bonding region 13 where the pair of pressingpieces 832 were pressed onto are formed with a pair of press marks 131.The first bonding portion 81 is across a straight line which connectsthe pair of press marks 113. Also, the second bonding portion 82 isacross a straight line which connects the pair of press marks 131. Byrepeating these steps, a plurality of wire 8 are bonded to respectivesemiconductor chips 41, 42, etc. in the lead frame 300 as shown in FIG.45. It should be noted here that the semiconductor chip 42 and the thirdelectrode portion 3 are connected to each other by a wire 8′. Wirebonding for this connection may be made by using the pressing pieces831; however, ball bonding may be employed instead, without using thepressing pieces 831.

Next, as shown in FIG. 46 and FIG. 47, a sealing resin portion 7 isformed. As shown in FIG. 46, the formation of the sealing resin portion7 is performed by means of a molding method using a metal mold 881. Asshown in the drawing, the die pads 11 and other components are heldinside the metal mold 881. Next, a resin material is injected into themetal mold 881, and then the resin material is allowed to set. Once theresin material is set, the metal mold 881 is taken away from the diepads 11 and other components as shown in FIG. 47. Thus, the sealingresin portion 7 is formed. In the steps of forming the sealing resinportion 7, a recess 75 is formed in the sealing resin portion 7 forexposure of the die pads 11.

Next, as shown in FIG. 48, a heat releasing layer 6 is fitted into therecess 75 of the sealing resin portion 7. Then, pressure and vibrationare applied to the heat releasing layer 6. The heat releasing layer 6may be heated, in addition. The pressure, vibration and heat soften thejunction layer 66 of the heat releasing layer 6. The softened junctionlayer 66 fills the recess 75. Also, the junction layer 66 becomes incontact with the recess side surface 752.

Next, the lead frame 300 is appropriately cut to complete themanufacture of the semiconductor device 101D which is illustrated inFIG. 33, etc.

Next, functions of the present embodiment will be described.

Pairs of pressing pieces 831, 832 hold on the regions where wires 8 areto be bonded, i.e., at places sandwiching the electrodes 411 or the wirebonding region 13. This makes it possible to prevent the die pad 11 andthe wire bonding region 13 from undue vibration and/or deformation dueto the pressure and/or vibration applied when bonding the wire 8.Therefore, it becomes possible to appropriately bond the wires 8.

The first bonding portion 81 is positioned across a straight lineconnecting the press marks 113 (tips of the pressing pieces 831). Thismakes it possible to appropriately prevent the vibration and deformationof the die pad 11 which can otherwise be caused by the pressure andvibration from the capillary 851 during the first bonding step.

The second bonding portion 82 is positioned across a straight lineconnecting the press marks 131 (tips of the pressing pieces 832). Thismakes it possible to appropriately prevent the vibration and deformationof the wire bonding region 13 which can otherwise be caused by thepressure and vibration from the capillary 851 during the second bondingstep.

The first bonding step to all of the electrodes 411 which are formed onthe semiconductor chip 41 is performed under the state where theelectrodes are sandwiched by the pressing pieces 831. This means thatthere is no need for moving the pair of pressing pieces 831 while thefirst bonding is being performed to a plurality of the electrodes 411.Therefore, the bonding steps are performed efficiently.

The present invention is not limited to the Embodiments described above.The present invention may be varied in many ways in any specificdetails. For example, as far as the metal layer is exposed from thesealing resin rear surface, the semiconductor device may not necessarilybe of an insertion mounting type but may have terminals for surfacemounting. Also, the invention is applicable not only to IPM devicesmentioned earlier but also to a semiconductor device which includes onlyone semiconductor chip and an island, but has a metal layer exposed froma rear surface of a sealing resin.

(Appendix 1) A wire bonding method comprising a wire bonding step ofbonding a wire while a pair of pressing pieces are pressed onto twoplaces on a bonding object at a space from each other, onto a positionin the bonding object between the pair of pressing pieces within adirection in which the pressing pieces are spaced from each other.(Appendix 2) The wire bonding method according to Appendix 1, whereinthe wire is bonded to a place on the bonding object, across a straightline which connects the pair of pressing pieces, in the wire bondingstep. (Appendix 3) The wire bonding method according to Appendix 1 ortwo, wherein the bonding object includes a die pad of a metal plate anda semiconductor chip mounted on the die pad and having one or moreelectrodes; in the wire bonding step, the pair of pressing pieces arepressed onto places in the die pad sandwiching the semiconductor chipwhile the wire is bonded to the electrodes. (Appendix 4) The wirebonding method according to Appendix 3, wherein the semiconductor chiphas a plurality of electrodes, and in the wire bonding step, the pair ofpressing pieces are pressed onto places sandwiching the plurality ofelectrodes while a wire is bonded individually to each of theelectrodes. (Appendix 5) The wire bonding method according to Appendix 1or 2, wherein the bonding object includes a wire bonding portion made ofa metal plate, and in the wire bonding step, the pair of pressing piecesare pressed onto the wire bonding portion while a wire is bonded to thewire bonding portion. (Appendix 6) The wire bonding method according toAppendix 1 or 2, wherein the bonding object includes: a die pad made ofa metal plate; a semiconductor chip mounted on the die pad and havingone or more electrodes; and a wire bonding portion spaced from the diepad; and in the wire bonding step, the pair of pressing pieces arepressed onto places in the die pad sandwiching the semiconductor chipwhile a wire is bonded to the electrodes, and after this wire bondingstep, an additional pair of pressing pieces are pressed onto the wirebonding portion and an additional wire bonding step is performed to thewire bonding portion. (Appendix 7) The wire bonding method according toAppendix 6, wherein the semiconductor chip has a plurality ofelectrodes, and in the wire bonding step, the pair of pressing piecesare pressed onto places sandwiching the plurality of electrodes while awire is bonded individually to each of the electrodes. (Appendix 8) Thewire bonding method according to one of Appendices 1 through 7, whereinthe wire is made of aluminum. (Appendix 9) The wire bonding methodaccording to Appendix 8, wherein pressure and vibration are applied tothe wire in the wire bonding step. (Appendix 10) A semiconductor devicecomprising: a die pad having a main surface and a rear surface facing inopposite directions; a semiconductor chip mounted on the main surface ofthe die pad and having one or more electrodes; and a sealing resinportion covering the die pad and the semiconductor chip; wherein the diepad is formed with a pair of press marks spaced from each other, and awire has an end bonded to a place on the electrode between the pair ofpress marks within a direction in which the pair of press marks arespaced from each other. (Appendix 11) The semiconductor device accordingto Appendix 10, wherein the end of the wire is bonded to cross astraight line which connects the pair of pressing pieces with eachother, on the electrode. (Appendix 12) The semiconductor deviceaccording to Appendix 10 or 11, further comprising a wire bondingportion spaced from the die pad, wherein the wire bonding portion isformed with an additional pair of press marks which are spaced from eachother, the wire has another end bonded to a place on the wire bondingportion between the additional pair of press marks within a direction inwhich the additional pair of press marks are spaced from each other.(Appendix 13) The semiconductor device according to Appendix 12, whereinsaid another end of the wire is bonded across a straight line whichconnects the additional pair of press marks with each other on the wirebonding portion. (Appendix 14) A semiconductor device comprising: a diepad including a main surface and a rear surface facing in oppositedirections; a semiconductor chip mounted on the main surface of the diepad and including one or more electrodes; leads each electricallyconnected to the semiconductor chip via a wire; and a sealing resinportion covering the die pad, the semiconductor chip and part of theleads; wherein the lead is formed with a pair of press marks on itssurface to sandwich a bonding place where the wire has its end bonded.(Appendix 15) The semiconductor device according to Appendix 11, whereinthe leads formed with the press marks have a wider region than the leadsnot formed with press marks. (Appendix 16) The semiconductor deviceaccording to Appendix 11 or 12, wherein the wire includes those ofdifferent thicknesses, and the press marks are formed only near thebonding places of the wires of a greater thickness. (Appendix 17) Thesemiconductor device according to Appendix 13, comprising a plurality ofthe semiconductor chips, wherein the thick wire is used only forelectrical connection between some of the semiconductor chips and theleads. (Appendix 18) The semiconductor device according to one ofAppendices 11 through 14, wherein the die pad surface sandwiching thesemiconductor chip is formed with a pair of press marks spaced from eachother so as to sandwich the semiconductor chip. (Appendix 19) Thesemiconductor device according to one of Appendices 11 through 15,comprising a plurality of the semiconductor chips including an outputtransistor and a controlling semiconductor chip therefor, wherein thepress marks spaced from each other on the lead are formed to sandwich aplace where the lead is bonded to the output transistor.

FIG. 49 is a sectional view showing a packaging structure when use ismade of a semiconductor device according to Embodiment 1E of the presentinvention.

A semiconductor device packaging structure 801 shown in FIG. 49 includesa semiconductor device 101E, a substrate 807 and a heat releasing member808.

The substrate 807 is capable of having a plurality of electriccomponents mounted thereon. The substrate 807 is made of an insulatingmaterial. The substrate 807 is formed with an unillustrated wiringpattern. The substrate 807 is formed with a plurality of holes 809. Theheat releasing member 808 is made of a material which has a relativelyhigh heat conductivity like a metal such as aluminum. The heat releasingmember 808 is fixed to the substrate 807 by an unillustrated supportingmember. The semiconductor device 101E is mounted on the substrate 807.In the present embodiment, the semiconductor device 101E is a so calledIPM (Intelligent Power Module) product. The semiconductor device 101E isused for such an application as electric power source control in an airconditioner, a motor controller, etc.

FIG. 50 is a plan view (partially unillustrated) of the semiconductordevice according to Embodiment 1E of the present invention, before leadsare bent. FIG. 51 is a bottom view of the semiconductor device accordingto Embodiment 1E of the present invention, before the leads are bent.FIG. 52 is a sectional view taken in lines LII-LII in FIG. 50. FIG. 53is an enlarged sectional view of a primary portion taken from FIG. 52.FIG. 49 represents a section taken in lines ILIX-ILIX in FIG. 50. InFIG. 52, each component is illustrated schematically for easiercomprehension.

The semiconductor device 101E shown in these drawings includes aplurality of first electrode portions 1, second electrode portions 2 andthird electrode portions 3; a plurality of semiconductor chips 41, 42;passive component chips 43; a heat releasing layer 6; a sealing resinportion 7 and wires 8. FIG. 50 shows the heat releasing layer 6 inbroken lines and the sealing resin portion 7 in imaginary lines.

The sealing resin portion 7 covers the plurality of the first electrodeportions 1, the second electrode portions 2, and the third electrodeportions 3; the semiconductor chips 41, 42; and the passive componentchips 43. The sealing resin portion 7 is made of a black epoxy resin forexample. As shown in FIG. 51 and FIG. 52, the sealing resin portion 7has a resin main surface 71, a resin bottom surface 72 and a resin sidesurface 73.

The resin main surface 71 is a flat surface which faces in a directionz1 and extends along an xy plane. The resin bottom surface 72 is a flatsurface which faces in a direction z2 that is opposite to the directionz1 and extends along an xy plane. The resin side surface 73 surroundsthe semiconductor chips 41, 42 and the passive component chips 43 inxy-plane view. The resin side surface 73 is connected to the resin mainsurface 71 and the resin bottom surface 72.

As clearly shown in FIG. 52, the sealing resin portion 7 is formed witha recess 75. The recess 75 recedes from the resin bottom surface 72. Therecess 75 has a recess bottom surface 751 and a recess side surface 752.The recess bottom surface 751 extends along an xy plane. The recess sidesurface 752 is connected to the resin bottom surface 72. The recess sidesurface 752 extends substantially in a direction z.

As shown in FIG. 50, the semiconductor chips 41, 42 and the passivecomponent chips 43 are rectangular in plan view. The semiconductor chip41 is a power chip such as an IGBT, MOS and diode, or an outputtransistor. The semiconductor chip 42 is an LSI chip such as a controlIC, or controls the semiconductor chip 41. The passive component chips43 are, for example, resisters, capacitors or other passive components.

The first electrode portions 1, the second electrode portions 2 and thethird electrode portions 3 in FIG. 50 are all made of an electricallyconductive material. An example of such an electrically conductivematerial is copper. The electrode portion shown in a bottom right regionin FIG. 50 is grounded.

Each of the plurality (four, in the present embodiment) of the firstelectrode portions 1 includes a die pad 11 (see FIG. 49, FIG. 50 andFIG. 52), a connecting region 12 (see FIG. 49 and FIG. 50), a wirebonding region 13 (see FIG. 49 and FIG. 50) and a lead 14 (see FIG. 49through FIG. 51). The first electrode portions 1 are spaced from eachother in the direction x.

Each die pad 11 is a flat plate extending along and parallel to an xyplane. The semiconductor chip 41 is disposed on the die pad 11. As shownin FIG. 52, a solder 991 is between the die pad 11 and the semiconductorchip 41. The solder 991 is an example of the electrically conductivejoining material according to the present invention. The solder 991 maybe replaced with an Ag paste. Solder has a relatively large thermalconductivity. The solder 991 can conduct heat efficiently from thesemiconductor chip 41 to the die pad 11. Each of the die pads 11 isexposed from the recess bottom surface 751.

As shown in FIG. 53, the semiconductor chip 41 is formed with rearsurface electrode 221. The rear surface electrode 413 is made of amaterial which has a relatively high solder wettability such as Ag, Au,Ni or an alloy containing any of these metals. In the presentembodiment, the semiconductor chip 41 has a rear surface 412 provided bythe rear surface electrode 413.

Each die pad 11 has a die pad main surface ill and a die pad rearsurface 112. The die pad main surface 111 faces in the direction z1whereas the die pad rear surface 112 faces in the direction z2. In otherwords, the die pad main surface 111 and the die pad rear surface 112 arearranged to face in the mutually opposite directions. The semiconductorchip 41 is disposed on the die pad main surface 111. The solder 991 isbetween the die pad main surface 111 and the semiconductor chip 41. Thedie pad rear surface 112 is located at the same position as the recessbottom surface 751 in a thickness direction (the direction z) of the diepad 11. However, the die pad rear surface 112 may be closer to anopening of the recess 75 than is the recess bottom surface 751.

The die pad 11 is made of Cu, an Fe—Ni alloy or Fe for example, so thedie pad main surface 111 has a relatively low solder wettability. In thepresent embodiment, an area of the join between the solder 991 and therear surface 412 of the semiconductor chip 41 is greater than an area ofthe join between the solder 991 and the die pad main surface 111.

As shown in FIG. 50, each connecting region 12 is disposed between thedie pad 11 and the wire bonding region 13, and connected to the die pad11 and to the wire bonding region 13. As shown in FIG. 49, theconnecting region 12 extends along a plane which is inclined withrespect to an xy plane. The connecting region 12 is inclined withrespect to an xy plane in such a manner that it goes farther in thedirection z1 as it is further away from the die pad 11.

Each wire bonding region 13 shown in FIG. 49 and FIG. 50 extends alongan xy plane. In the direction z, each wire bonding region 13 is on aside more toward the direction z1 than is the die pad 11. A wire 8 isbonded to one of the wire bonding regions 13 and to one of thesemiconductor chips 41. Thus, electrical conductivity is establishedbetween said one of the wire bonding regions 13 and said one of thesemiconductor chips 41. The leads 14 are connected to the wire bondingregions 13. Each lead 14 extends along the direction y. The lead 14 hasa portion extending out of the resin side surface 73 of the sealingresin portion 7. In the present embodiment, the leads 14 are forinsertion mounting. As shown in FIG. 49, when mounting the semiconductordevice 101E on the substrate 807, the leads 14 are bent and insertedthrough the holes 809. For fixing the leads 14 in the substrate 807, theholes 809 are filled with solder layers 810.

As shown in FIG. 50, each of the plurality (three, in the presentembodiment) of the second electrode portions 2 includes a wire bondingregion 23 and a lead 24. The second electrode portions 2 are spaced fromeach other in the direction x.

Each wire bonding region 23 extends along an xy plane. In the directionz, each wire bonding region 23 is on a side more toward the direction z1than is the die pad 11. A wire 8 is bonded to one of the wire bondingregions 23 and to one of the semiconductor chips 41. Thus, electricalconductivity is established between said one of the wire bonding regions23 and said one of the semiconductor chips 41. The leads 24 areconnected to the wire bonding regions 23. Each lead 24 extends in thedirection y. The lead 24 has a portion extending out of the resin sidesurface 73 of the sealing resin portion 7. In the present embodiment,the leads 24 are for insertion mounting. Though not illustrated, whenmounting the semiconductor device. 101E on the substrate 807, the leads24 are bent and inserted through the holes 809 like the leads 14.

The third electrode portions 3 shown in FIG. 49, FIG. 50 includes aplurality of control die pads 31 and a plurality of leads 32. Thecontrol die pads 31 and the leads 32 are respectively disposed at thesame positions in the direction z. On each control die pad 31, thesemiconductor chip 42 or the passive component chips 43 is disposed. Ajunction layer (not illustrated) is formed between the control die pad31 and the semiconductor chip 42, and between the control die pads 31and the passive component chips 43. The control die pads 31 need nothave its rear surface faced to the heat releasing layer 6 or exposed.

Each lead 32 has a portion extending out of the resin side surface 73 ofthe sealing resin portion 7. In the present embodiment, the leads 32 arefor insertion mounting. As shown in FIG. 49, when mounting thesemiconductor device 101E on the substrate 807, the leads 32 are bentand inserted through the holes 809. As has been described in relationwith the leads 14, the holes 809 are filled with solder layers 810 forfixing the leads 32 in the substrate 809. A wire 8 is bonded to one ofthe leads 32 and to one of the semiconductor chips 42. Thus, electricalconductivity is established between said one of the leads 32 and saidone of the semiconductor chips 42. Also, a wire 8 is bonded to one ofthe semiconductor chip 42 and to one of the passive component chips 43.

As shown in FIG. 52, the heat releasing layer 6 is in the recess 75 inthe sealing resin portion 7. The heat releasing layer 6 is surrounded bythe recess side surface 752. In the present embodiment, the heatreleasing layer 6 is a flat plate extending along and parallel to an xyplane. In the present embodiment, the heat releasing layer 6 isconstituted by the metal layer 65 and the junction layer 66. The metallayer 65 is on a side toward the z2 direction, and is made of Cu,aluminum or ceramics, for example, having a thickness of approximately105 μm. The junction layer 66 is on a side toward the z1 direction withrespect to the metal layer 65 and joins the metal layer 65 to the diepad rear surfaces 112 of the die pads 11. The junction layer 66 is madeof an insulating resin for example, and has a thickness of approximately250 μm for example. The resin becomes soft when it receives pressure andvibration in a manufacturing step of the semiconductor device 101E, andis in direct contact with all of the die pads 11 on which thesemiconductor chips 41 are mounted. The metal layer 65 may have a region(s) slightly out of the resin bottom surface 72. The junction layer 66is in contact with the recess side surface 752.

The heat releasing layer 6 is for quickly releasing heat which wasgenerated in the semiconductor chip 41 to outside of the semiconductordevice 101E. In order to quickly release the heat generated by thesemiconductor chip 41 to outside of the semiconductor device 101E, theheat releasing layer 6 should be made of a material of a large thermalconductivity. While a larger thermal conductivity is preferred, therecan be a potential problem that the metal layer 65 will peel off, if theheat releasing layer's thermal expansion coefficient differs greatlyfrom that of the sealing resin portion 7. Preferably, therefore, theheat releasing layer 6 is of a material which has a larger thermalconductivity than that of a material which constitutes the sealing resinportion 7, and a similar thermal expansion coefficient to that of thematerial which constitutes the sealing resin portion 7. The heatreleasing layer 6 is faced directly to all of the die pads 11. As shownin FIG. 51, the heat releasing layer 6 covers all of the die pads 11entirely in xy plane view (i.e., as viewed in the thickness direction ofthe heat releasing layer 6).

As shown in FIG. 51 and FIG. 52, the heat releasing layer 6 has a heatreleasing layer main surface 61 and a heat releasing layer rear surface62. The heat releasing layer main surface 61 faces in the direction z1.The heat releasing layer main surface 61 covers the die pad rearsurfaces 112 and the recess bottom surfaces 751 of all of the die pads11 in xy-plane view. The heat releasing layer main surface 61 is indirect contact with the die pad rear surface 112 and the recess bottomsurface 751. The heat releasing layer rear surface 62 faces in thedirection z2 which is a direction opposite to the direction in which theheat releasing layer main surface 61 faces. The heat releasing layerrear surface 62 is not covered by the sealing resin portion 7 and isexposed from the sealing resin portion 7.

Next, a method of making the semiconductor device 101E will bedescribed. Drawings for describing the method will use the samereference symbols as those used thus far in identifying those describedthus far.

First, as shown in FIG. 54, a lead frame 300 which includes a pluralityof die pads 11, 31 is prepared. Then, the following steps are performedto apply solder paste 991′. The solder paste 991′ is an example of theelectrically conductive joining paste according to the presentinvention. The solder paste 991′ may be replaced with an Ag paste orother paste containing a metal and an organic solvent. As shown in thedrawing, areas to which the solder paste 991′ is applied are smallerthan and included within corresponding areas of the semiconductor chips41, 42 or of the passive component chips 43 in plan view. Hereinafter,FIG. 55 through FIG. 59 will be referenced in describing, as an example,how the solder paste 991′ is applied to the die pad 11 and then thesemiconductor chip 41 is joined thereto. It should be noted here thatfor the sake of better heat release, the following method may be usedonly in those areas on a die pad 11 where a plurality of semiconductorchips 41 are to be mounted, with the remaining area of the electricallyconductive joining paste treated in a conventional method.

First, as shown in FIG. 55, a mask layer 992 is prepared. The mask 992is formed with a plurality of openings 993. These openings 993correspond to the application areas of the solder paste 991′ shown inFIG. 54. Using the mask 992, the lead frame 300 is covered.

Next, as shown in FIG. 56, solder paste 991′ is applied. The applicationis performed by filling the openings 993 in the mask 992 with the solderpaste 991′. Next, as shown in FIG. 57, the mask 992 is removed, whichleaves the solder paste 991′ applied in the desired areas.

Next, the semiconductor chips 41 are placed on the areas of the solderpaste 991′. The areas to which the solder paste 991′ is applied aresmaller than the areas of the semiconductor chips 41 in plan view. Thesemiconductor chips 41 are placed so as to entirely conceal and furtheroverhang these areas of the solder paste 991′. In this process,placement is also made for semiconductor chips 42 and passive componentchips 43 which are described earlier.

Next, the lead frame 300 is placed and heated in a reflow furnace forexample, to melt the solder paste 991′. Since the semiconductor chip 41has a rear surface 412 (the rear surface electrode 413) made of, e.g.,Ag or Au which has a relatively high solder wettability, the moltensolder paste 991′ spread over the entire surface. On the other hand, themain surface 111 of the die pad 11 is made of Cu, an Fe—Ni alloy or Fewhich has a relatively low solder wettability, and therefore, the moltensolder paste 991′ does not tend to spread. Consequently, the solder 991as shown in FIG. 59 is obtained from the heating in the reflow furnace.In the solder 991, an area shared with to the rear surface 412 of thesemiconductor chip 41 is greater than an area of shared with the mainsurface 111 of the die pad 11. FIG. 60 shows a lead frame 300 which wastaken out of the reflow furnace.

Next, as shown in FIG. 61, a wire 8 is bonded to each of thesemiconductor chips 41, 42, etc., and to their corresponding leads.

Next, as shown in FIG. 62 and FIG. 63, a sealing resin portion 7 isformed. As shown in FIG. 62, the formation of the sealing resin portion7 is performed by means of a molding method using a metal mold 881. Asshown in the drawing, the die pads 11 and other components are heldinside the metal mold 881. Next, a resin material is injected into themetal mold 881, and then the resin material is allowed to set. Once theresin material is set, the metal mold 881 is taken away from the diepads 11 and other components as shown in FIG. 63. Thus, the sealingresin portion 7 is formed. In the steps of forming the sealing resinportion 7, a recess 75 is formed in the sealing resin portion 7 forexposure of the die pads 11.

Next, as shown in FIG. 64, a heat releasing layer 6 is fitted into therecess 75 of the sealing resin portion 7. Then, pressure and vibrationare applied to the heat releasing layer 6. The heat releasing layer 6may be heated, in addition. The pressure, vibration and heat soften thejunction layer 66 of the heat releasing layer 6. The softened junctionlayer 66 fills the recess 75. Also, the junction layer 66 becomes incontact with the recess side surface 752.

Next, the lead frame 300 is appropriately cut to complete themanufacture of the semiconductor device 101E which is illustrated inFIG. 50, etc.

Next, functions of the present embodiment will be described.

According to the present embodiment, solder paste 991′ is applied to anarea which is smaller than a plan-view area of the semiconductor chip41, and the semiconductor chip 41 is placed to entirely conceal andfurther overhang the pasted area. If the solder paste 991′ is heatedunder this state, the solder 991 tends to remain within thesemiconductor chip 41 in plan view. Therefore, it becomes possible toprevent such a situation that mutually adjacent two pieces of solder 991which are formed for joining two semiconductor chips 41 to respectivedie pad main surface 111 make an undue contact with each other, or asituation that only part of the solder paste reaches an end of the diepad. Thus, the arrangement makes it possible to eliminate soldererosion, or a problem that surface tension, for example, in the solderpaste will move the semiconductor chips off their predeterminedpositions. Hence it becomes possible to dispose the semiconductor chipsonto their predetermined places for easier wiring operations. This alsomakes it possible to decrease a distance between mutually adjacentchips, making it possible to further decrease the outer size of thesemiconductor device.

The rear surface 412 of the semiconductor chip 41 is made to have arelatively high solder wettability while the main surface 111 of the diepad 11 is made to have a relatively low solder wettability. This makesit possible to appropriately prevent the solder 991 from spreadingunduly.

The mask 992 is used when applying the solder paste 991′. This issuitable for applying the solder paste 991′ more accurately in intendedregions. It should be noted here that the solder paste 991′ may beapplied in other methods than using the mask 992. For example,application may be made by dropping solder paste 991′ from a syringe.

The present invention is not limited to the Embodiments described above.The present invention may be varied in many ways in any specificdetails. For example, the invention is applicable not only to IPMsemiconductor devices described thus far but also to other semiconductordevices such as a power transistor which includes only one semiconductorchip and an island, as far as the semiconductor device make use of athick and hard wire made of, e.g., aluminum. Further, the invention isalso applicable not only to those devices of an insertion mounting typebut also to those which have terminals for surface mounting.

(Appendix 1) A method for making a semiconductor device comprising: anapplication step of applying an electrically conductive joining paste ona main surface of a die pad; a placement step of placing a semiconductorchip, which is larger than an area covered by the electricallyconductive joining paste as viewed in a direction in which the mainsurface faces, by making a rear surface of the semiconductor chipcontact with the electrically conductive joining paste so that the areacovered by the electrically conductive joining paste is contained by therear surface as viewed in the direction in which the main surface faces;and a joining step of softening and then hardening the electricallyconductive joining paste thereby forming an electrically conductivejoining material. (Appendix 2) The method for making a semiconductordevice according to Appendix 1, wherein the electrically conductivejoining paste is provided by a solder paste. (Appendix 3) The method formaking a semiconductor device according to Appendix 2, wherein the mainsurface is covered by a mask which has openings, and the openings arefilled with the electrically conductive joining paste, in theapplication step. (Appendix 4) The method for making a semiconductordevice according to one of Appendices 1 through 3, wherein the rearsurface of the semiconductor chip has a higher wettability to theelectrically conductive joining paste than the main surface of the diepad. (Appendix 5) The method for making a semiconductor device accordingto Appendix 4, wherein the rear surface of the semiconductor chip ismade of Ag, Au, Ni or an alloy containing one of these metals whereasthe main surface of the die pad is made of Cu, an FeNi alloy or Fe.(Appendix 6) A semiconductor device comprising: a die pad having a mainsurface; a semiconductor chip having a rear surface; and an electricallyconductive joining material between the main surface of the die pad andthe rear surface of the semiconductor chip, providing a junction betweenthe die pad and the semiconductor chip; wherein the rear surface of thesemiconductor chip and the electrically conductive joining materialshare a larger junction area between the two than do the main surface ofthe die pad and the electrically conductive joining material. (Appendix7) The semiconductor device according to Appendix 6, wherein theelectrically conductive joining material is provided by a solder.(Appendix 8) The semiconductor device according to Appendix 6, whereinthe rear surface of the semiconductor chip has a higher wettability tothe electrically conductive joining paste than the main surface of thedie pad. (Appendix 9) The semiconductor device according to Appendix 8,wherein the rear surface of the semiconductor chip is made of Ag, Au, Nior an alloy containing one of these metals whereas the main surface ofthe die pad is made of Cu, an FeNi alloy or Fe. (Appendix 10) Asemiconductor device comprising: die pads each having a main surface anda rear surface facing in opposite directions; a plurality ofsemiconductor chips mounted on the main surface of one of the die pads;and an electrically conductive joining material between the main surfaceof the die pad and a rear surface of each semiconductor chip, providinga junction between the die pad and each of the semiconductor chips;wherein the rear surface of each semiconductor chip shares with itscorresponding electrically conductive joining material a larger junctionarea between the two than does the main surface of said die pad sharewith said electrically conductive joining material formed for saidsemiconductor chip. (Appendix 11) The semiconductor device according toAppendix 9, wherein the semiconductor chip includes a plurality ofoutput transistors and a controlling semiconductor chip therefor, theabove-described relationship between two junction areas being true inthe plurality of output transistors. (Appendix 12) The semiconductordevice according to Appendix 10, further comprising: a plurality ofleads each for an output from one of the output transistors; and aplurality of wires each connecting one of the output transistors with acorresponding one of the leads; the wire being made of aluminum.

LEGEND

101A-101E, 102A-102C semiconductor device; 1 first electrode portion; 11die pad; 111 main surface; 111 die pad main surface; 112 die pad rearsurface; 113 press mark; 12 bonding region; 13 wire bonding region; 131(additional) press mark; 14 lead; 2 second electrode portion; 23 wirebonding portion; 24 lead; 3 third electrode portion; 31 control die pad;32 lead; 300 lead frame; 41 semiconductor chip; 411 electrode; 412 rearsurface; 413 rear surface electrode; 42 semiconductor chip; 43 passivecomponent chip; 6 heat releasing layer; 61 heat releasing layer mainsurface; 611 groove; 62 heat releasing layer rear surface; 631 firstside surface; 632 intermediate surface; 633 second side surface; 634first angled region; 645 second angled region; 65 metal layer; 66junction layer; 69 junction layer; 7 sealing resin portion; 71 resinmain surface; 72 resin bottom surface; 73 resin side surface; 75 recess;751 recess bottom surface; 752 recess side surface; 753 recess groove;754 recess first side surface; 755 recess second side surface; 756recess support surface; 8 wire; 81 first bonding portion; 82 secondbonding portion; 85 bonding apparatus; 801 packaging structure; 807substrate; 808 heat releasing member; 809 hole; 810 solder layer; 810solder layer; 831 pressing piece; 832 (additional) pressing pieces; 851capillary; 852 guide; 853 cutter; 854 base; 855 arm; 856 wire reel; 860jig; 861 support surface; 862 support surface; 881 metal mold; 991solder (electrically conductive joining material); 991 junction layer;991′ solder paste (electrically conductive joining paste); 992 mask; 993opening

The invention claimed is:
 1. A semiconductor device comprising: a diepad including a main surface and a rear surface that face in oppositedirections; a semiconductor chip mounted on the main surface of the diepad; a sealing resin portion covering the die pad and the semiconductorchip and formed with a recess for exposure of the rear surface of thedie pad; and a heat releasing layer disposed in the recess; wherein therecess is formed with a groove located outside the die pad in adirection in which the rear surface extends, the groove including aportion closer to the main surface than to the rear surface, and whereinthe heat releasing layer includes a junction layer contacting the rearsurface of the die pad and having a part filling the groove.
 2. Thesemiconductor device according to claim 1, wherein the heat releasinglayer includes a metal layer laminated on a side of the junction layeropposite to the die pad.
 3. The semiconductor device according to claim2, wherein the metal layer is made of Cu.
 4. The semiconductor deviceaccording to claim 2, wherein the junction layer is made of a resin. 5.The semiconductor device according to claim 2, wherein the metal layerpartially protrudes from the recess in a thickness direction of themetal layer.
 6. The semiconductor device according to claim 2, whereinthe groove is disposed outside the metal layer in the direction in whichthe rear surface extends.
 7. The semiconductor device according to claim6, wherein the recess includes a bottom surface having a region disposedbetween the metal layer and the groove.
 8. The semiconductor deviceaccording to claim 2, wherein the groove is slanted in such a mannerthat as it goes away from the die pad in the direction in which the rearsurface extends, it comes from the rear surface toward the main surfacein the thickness direction of the die pad.
 9. The semiconductor deviceaccording to claim 7, wherein the recess includes: a first side surfacewhich is outside the die pad in the direction in which the rear surfaceextends, the first side surface being connected to the bottom surface; asupport surface connected to the first side surface and facing in adirection in which the rear surface faces; and a second side surfaceconnected to the support surface and located between the die pad and thefirst side surface in the direction in which the rear surface extends;wherein the metal layer overlaps the first side surface in a thicknessdirection of the die pad, and includes an outer edge at least a part ofwhich is disposed between the first side surface and the second sidesurface in the direction in which the rear surface extends.
 10. Thesemiconductor device according to claim 9, wherein a part of thejunction layer is disposed between the support surface and the metallayer.
 11. A semiconductor device comprising: a plurality of die padseach including a main surface and a rear surface facing in oppositedirections; a plurality of semiconductor chips each mounted on the mainsurface of a corresponding one of the die pads; a sealing resin portionformed with a recess for common exposure of the rear surfaces of atleast some of the die pads while covering all of the die pads and thesemiconductor chips; and a heat releasing layer disposed in the recess;wherein the recess is formed with a groove disposed outside the die padson the rear surface side and offset to the main surface than the rearsurface, and wherein the heat releasing layer includes a junction layerbeing in contact commonly with the rear surface of each die pad andhaving a part filling the groove.